Support for elastic 7.x

[antalk]

Describe the bug

I have followed the setup on the wiki, but i get errors when actually logging:

Warnings: [[types removal] Specifying types in document index requests is deprecated, use the typeless endpoints instead (/{index}/_doc/{id}, /{index}/_doc, or /{index}/_create/{id}).]

i believe this is due to the change with multiple types for an index which are not supported anymore in elastic 7.

To Reproduce
Steps to reproduce the behavior:

Get an elastic 7 instance running and connect to it using the setup on this wiki.

Expected behavior

new documents inserted into elastic

**Desktop

• Windows 7
• Elastic 7.1.0

Additional context
stacktrace:

WARNING: request [POST http://:9200//doc?timeout=1m] returned 1 warnings: [299 Elasticsearch-7.1.0-606a173 "[types removal] Specifying types in document index requests is deprecated, use the typeless endpoints instead (/{index}/_doc/{id}, /{index}/_doc, or /{index}/_create/{id})."]
ERROR StatusLogger An exception occurred processing Appender example-elastic-appender
ElasticsearchStatusException[Elasticsearch exception [type=illegal_argument_exception, reason=Rejecting mapping update to [mulesoft] as the final mapping would have more than 1 type: [_doc, doc]]]
at org.elasticsearch.rest.BytesRestResponse.errorFromXContent(BytesRestResponse.java:177)
at org.elasticsearch.client.RestHighLevelClient.parseEntity(RestHighLevelClient.java:1706)
at org.elasticsearch.client.RestHighLevelClient.parseResponseException(RestHighLevelClient.java:1683)
at org.elasticsearch.client.RestHighLevelClient.internalPerformRequest(RestHighLevelClient.java:1446)
at org.elasticsearch.client.RestHighLevelClient.performRequest(RestHighLevelClient.java:1403)
at org.elasticsearch.client.RestHighLevelClient.performRequestAndParseEntity(RestHighLevelClient.java:1373)
at org.elasticsearch.client.RestHighLevelClient.index(RestHighLevelClient.java:821)
at com.github.ivanocortesini.log4j.elastic.client.ElasticClient.storeDocument(ElasticClient.java:131)
at com.github.ivanocortesini.log4j.elastic.client.ElasticClient.storeXContentDocument(ElasticClient.java:107)
at com.github.ivanocortesini.log4j.elastic.appender.ElasticAppender.append(ElasticAppender.java:92)
at org.apache.logging.log4j.core.config.AppenderControl.tryCallAppender(AppenderControl.java:156)
at org.apache.logging.log4j.core.config.AppenderControl.callAppender0(AppenderControl.java:129)
at org.apache.logging.log4j.core.config.AppenderControl.callAppenderPreventRecursion(AppenderControl.java:120)
at org.apache.logging.log4j.core.config.AppenderControl.callAppender(AppenderControl.java:84)
at org.apache.logging.log4j.core.config.LoggerConfig.callAppenders(LoggerConfig.java:464)
at org.apache.logging.log4j.core.config.LoggerConfig.processLogEvent(LoggerConfig.java:448)
at org.apache.logging.log4j.core.config.LoggerConfig.log(LoggerConfig.java:431)
at org.apache.logging.log4j.core.config.LoggerConfig.log(LoggerConfig.java:406)
at org.apache.logging.log4j.core.config.AwaitCompletionReliabilityStrategy.log(AwaitCompletionReliabilityStrategy.java:63)
at org.apache.logging.log4j.core.Logger.logMessage(Logger.java:146)
at org.apache.logging.log4j.spi.AbstractLogger.tryLogMessage(AbstractLogger.java:2170)
at org.apache.logging.log4j.spi.AbstractLogger.logMessageTrackRecursion(AbstractLogger.java:2125)
at org.apache.logging.log4j.spi.AbstractLogger.logMessageSafely(AbstractLogger.java:2108)
at org.apache.logging.log4j.spi.AbstractLogger.logMessage(AbstractLogger.java:2002)
at org.apache.logging.log4j.spi.AbstractLogger.logIfEnabled(AbstractLogger.java:1974)
at org.apache.logging.log4j.spi.AbstractLogger.info(AbstractLogger.java:1311)
at nl.stater.horus.test.TestLogstash.testLogStashLoggeing(TestLogstash.java:44)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:538)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:760)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:460)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:206)
Suppressed: org.elasticsearch.client.ResponseException: method [POST], host [:9200], URI [//doc?timeout=1m], status line [HTTP/1.1 400 Bad Request]