Trigger build workflows based on changed files

[sven-dmlr]

Situation

Currently the workflows

• "Java & Go CI" (build Java + Go and run integration tests)
• "Build SecHub GHA (scan)" (build scan Action and run its unit tests)
  are not working properly (commits to master, develop, ... never trigger a run but they should)

Additionally both workflows are started even if they aren't suppoed to run (skipped by if: statement.
This looks a bit confusing.

Wanted

The build workflows are triggered based on the change's (Pr or commit) content.

Solution

Use paths: and paths-ignore
instead of branches plus if:.

See https://docs.github.com/en/actions/writing-workflows/workflow-syntax-for-github-actions#onpushpull_requestpull_request_targetpathspaths-ignore

Also the docs can be updated: There is no more need for gha_feature-xyz branch names.