New release pipeline in operator

[Jorres]

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

• No changelog
• Build and release (pushing docker image + helm chart to every configured registry) happens on push to master, every commit, automatically
• Developer has to update version and appVersion in Chart.yaml manually, which is prone to human error

What is the new behavior?

• New create-release-pr workflow, collects all changes generated by changie, generates a changelog for the new release, and creates a PR with a new CHANGELOG.md
• upload-artifacts workflow has been updated:
  • it triggers only when CHANGELOG.md file is changed or manually
  • marks the latest commit with a latest tag supplied by changie
  • substitutes the version placeholders in Chart.yaml with this new version
  • builds and uploads artifacts, as usual (this part stayed the same)
  • creates a Github release
• updated documentation to comply with the new changes

Additional information

• fixed the lint job, it started failing some time ago and is fixed by updating both golang-ci-lint github action and golang-ci-lint binary itself to the latest version.