Add update version workflow

[xsalefter]

Original issue: killbill/killbill-oss-parent#751

POC: https://github.com/xsalefter/kb-oss-parent

1. The update-version.yml is doing the same as what the POC done here.

2. The update-version.yml then uses by release-repo-dispatch.yml file. In killbill project, this release-repo-dispatch.yml file will created in killbill-oss-parent project with the same name (PR created later).

3. After update-version.yml executed successfully, release-repo-dispatch.yml will call ci.yml. In killbill project, release-repo-dispatch.yml will doing the same thing: calling its ci.yml file.

4. Once ci.yml executed sucessfully, release-repo-dispatch.yml file will call release.yml. In killbill project, release-repo-dispatch.yml will doing the same thing: calling release.yml. Killbill's release.yml will have minor modification.

5. The release-repo-dispatch.yml will be triggered by other repositories that sent a repository_dispatch event. killbill-commons is one of them.

Thus, when killbill-commons (or any other repositories) released successfully, then its version will getting updated in killbill-oss-parent, trigger CI, and then try to release the up-to-date killbill-oss-parent automatically.

Note: There's one commit that have nothing to do with original issue: adding .gitignore file for intellij files.

[sbrossie]

Does it really work for the multi-module repo - e.g killbill-commons; Don't we need to update the pom.xml from all the children directory, e.g https://github.com/killbill/killbill-commons/blob/master/automaton/pom.xml#L25 ?

If this is the case, why not using mvn versions:set -DnewVersion=${{github.event.client_payload.property_value}} ?

[xsalefter]

The purpose of this update-version.yml is to update and commit this /project/properties/<any> in pom.xml:

<project>
  <properties>
    <!-- this will be updated -->
    <killbill-commons.version>1.2.3</killbill-commons.version>
  </properties>
</project>

meanwhile, AFAIK mvn versions:set to actually update its/dependencies version.

Nevertheless, now I think this update-version.yml would never used outside of killbill-oss-parent repository 🤔 . Should I just remove this and put in killbill-oss-parent instead?

[xsalefter]

Closed this PR as we don't need this.