Fixes: https://github.com/spring-projects/spring-retry/issues/480
* Add `flatten-maven-plugin` to resolve properties
and remove unnecessary build info from the final POM of the artifact to install/deploy
* Revert `version` extraction from POM via `sed` command in the build action
* Remove `flatten.clean` from the Maven Flatter Plugin, since `.flattened-pom.xml` generated file is landed in the `/target` dir
* Add `pomElements/profiles` for removal in the result `.flattened-pom.xml`
Since there is no `revision` property in POM, we cannot use `sed` command to extract project version from the POM.
* Use more Maven-friendly `mvn help:evaluate -Dexpression="project.version" -q -DforceStdout` command to get the current project version
* Remove tentative `finish_release_tmp.yml` since `actions\build` has been fixed now