Fix build

Issue gh-2327

Author: rwinch

buildSrc/src/main/groovy/io/spring/gradle/convention/JacocoPlugin.groovy

@@ -34,7 +34,7 @@ class JacocoPlugin implements Plugin<Project> {
 			project.tasks.check.dependsOn project.tasks.jacocoTestReport
 
 			project.jacoco {
-				toolVersion = '0.8.2'
+				toolVersion = '0.8.7'
 			}
 		}
 	}

buildSrc/src/test/java/io/spring/gradle/convention/JavadocApiPluginITest.java

@@ -28,7 +28,7 @@ public void multiModuleApi() throws Exception {
 				.build();
 		assertThat(result.task(":api").getOutcome()).isEqualTo(TaskOutcome.SUCCESS);
         File allClasses = new File(testKit.getRootDir(), "build/api/allclasses-noframe.html");
-		File index = new File(testKit.getRootDir(), "build/api/allclasses.html");
+		File index = new File(testKit.getRootDir(), "build/api/allclasses-index.html");
 		File listing = allClasses.exists() ? allClasses : index;
 		String listingText = FileUtils.readFileToString(listing);
 		assertThat(listingText).contains("sample/Api.html");