automate generation of readme.md

[nschad]

What this Issue is supposed to do
Basically we want to automate the annoying task of updating the README.md since we use helm-docs for generating the helm value table for the chart. By automatically having a workflow which reacts on every PR we could just generate the README.md for the contributor and automatically add it to the PR (unless they opt-out of us pushing to their fork at which point the workflow would just fail)

Issues we encountered

• Workflows are not run if its triggered by a workflow unless you are pushing with a PAT
• Setting skip ci on the updated README.md commit message causes the whole workflow to seize up since a now required workflow (the ct/lint job) is skipped
• Ignoring ct/lint jobs for none code-changes PRs (just documentation) leads to the same problem as above

Solutions

• Having an Action push with PAT (instead of the GITHUB_TOKEN) solves the first problem