RELEASE: improve CI-based release docs

RELEASE.md

@@ -1,6 +1,21 @@
 # Release process
 
-## Release branch and tags
+## Automated
+
+1. Go to Gitlab's Pipelines in the repository.
+2. Click on the grey job with an arrow in it (`development` branch).
+3. Click on 'Create Release' manually job of the pipeline, not on the play button!
+4. Enter the following key-value variable:
+    - Key: `RELEASE_TAG_NAME`
+    - Value: The git tag you want, for example: `1.2.3`
+5. Press 'Run job'
+
+All release steps are automatically executed including syncing the `master` branch, git tags, Maven, Docker, etc.
+Once the job completes, make manually a GitHub Release from the tag your created on GitHub.
+
+## Manually
+
+### Release branch and tags
 
 1. Make a new release branch (named `release/X.Y.Z`)
 2. Bump version number in `pom.xml`
@@ -11,13 +26,13 @@
 7. Create a git tag: `git tag $TAG` on `master`.
 8. Push tag: `git push --tags`
 
-## Docker image
+### Docker image
 
 1. Run `docker build -t rmlio/rmlmapper-java:$TAG .` to generate a Docker image for your `$TAG`.
 2. Repeat this for the `latest` tag: `docker build -t rmlio/rmlmapper-java:latest`
 3. Push Docker images to Docker Hub: `docker push rmlio/rmlmapper-java:$TAG` and `docker push rmlio/rmlmapper-java:latest`.
 
-## Deploy on Central Repository
+### Deploy on Central Repository
 
 The following steps deploy a new version to the Central Repository,
 based on [this tutorial](https://central.sonatype.org/pages/apache-maven.html).
@@ -30,15 +45,15 @@ copy `settings.example.xml` to `~/.m2/settings.xml`.
 5. Make sure `JAVA_HOME` is properly set for your setup. Example: `export JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64`
 6. Deploy the latest release via `mvn clean deploy -P release -DskipTests=true`.
 
-## Create a release on Github
+### Create a release on Github
 
 1. Update the `master` and `development` branches on Github.
 2. Go to the Github repo and make a new release.
 3. Select the tag you created earlier.
 4. Add the content of `CHANGELOG.md` in the release notes
 5. Append the fat jar you generated earlier as release binaries
 
-## Create a Merge Request to Alpine Linux's aports
+### Create a Merge Request to Alpine Linux's aports
 
 1. Make sure you have `pmbootstrap` installed and ran `pmbootstrap init`, see https://wiki.postmarketos.org/wiki/Installing_pmbootstrap#Installing_automatically
 3. Fork and clone aports: https://gitlab.alpinelinux.org/alpine/aports
@@ -51,7 +66,7 @@ copy `settings.example.xml` to `~/.m2/settings.xml`.
 10. Push to your fork and create a Merge Request in Alpine Linux's Gitlab.
 11. If the CI properly passes, maintainers will merge it in the next few hours or days.
 
-## Re-run the R2RML implementation report test cases
+### Re-run the R2RML implementation report test cases
 
 1. Re-run them for this `$TAG`
 2. Make a merge request to the `rmlio` website