added docu for the new step

documentation/docs/steps/abapLandscapePortalUpdateAddOnProduct.md

@@ -0,0 +1,55 @@
+# ${docGenStepName}
+
+## ${docGenDescription}
+
+## Prerequisites
+
+- Please make sure, that the service landscape-portal-api-for-s4hc with plan api was assigned as entitlement to the subaccount, where you are about to deploy addon product.
+- Please make sure, that before deploying addon product, an instance of landscape-portal-api-for-s4hc (plan api) was created, and a service key with x509 authentication mechanism was created for the instance. The service key needs to be stored in the Jenkins Credentials Store.
+- Please make sure, that the system to deploy addon product is active, and the descriptor file with deployment information is available.
+
+## ${docGenParameters}
+
+## ${docGenConfiguration}
+
+## ${docJenkinsPluginDependencies}
+
+## Example: Configuration in the config.yml
+
+The recommended way to configure your pipeline is via the config.yml file. In this case, calling the step in the Jenkinsfile is reduced to one line:
+
+```groovy
+abapLandscapePortalUpdateAddOnProduct script: this
+```
+
+The configuration values for the addon update can be passed through the `config.yml` file:
+
+```yaml
+steps:
+  abapLandscapePortalUpdateAddOnProduct:
+    landscapePortalAPICredentialsId: 'landscapePortalAPICredentialsId'
+    abapSystemNumber: 'abapSystemNumber'
+    addonDescriptorFileName: 'addon.yml'
+    addonDescriptor: 'addonDescriptor'
+```
+
+## Example: Configuration in the Jenkinsfile
+
+The step, including all parameters, can also be called directly from the Jenkinsfile. In the following example, a configuration file is used.
+
+```groovy
+abapLandscapePortalUpdateAddOnProduct (
+  script: this,
+  landscapePortalAPICredentialsId: 'landscapePortalAPICredentialsId'
+  abapSystemNumber: 'abapSystemNumber'
+  addonDescriptorFileName: 'addon.yml'
+  addonDescriptor: 'addonDescriptor'
+)
+```
+
+The file `addon.yml` would look like this:
+
+```yaml
+addonProduct: some-addon-product
+addonVersion: some-addon-version
+```