fix(other): github cache in workflow

[ulfgebhardt]

🍰 Pullrequest

Fix vulnerabilities that have come into our CI through the workflow refactoring.

• allow manual re-run of failed jobs with intact workflow cache (do not delete cache, if a preceeding job failed)

  

  

• handle cache cleanup to avoid "cache thrashing"

Todo

• use runner id for distinguishable cache naming
• run cache deletion job only, if
  • workflow's file change condition is true
  • needed preceding jobs ran successfully
• add recommended branch cache cleanup at pr closing workflow

Thanx @ulfgebhardt for the good hints.