cleanup: add descriptions, update auth-token usage

[steffyP]

General cleanup:

• add description to the action.yml files
• updated the use of LOCALSTACK_AUTH_TOKEN and remove outdated references to api key
  • including README update
  • replace usage of secrets.LOCALSTACK_API_KEY with secrets.LOCALSTACK_AUTH_TOKEN
• updated the LICENSE copyright year + owner

Followup tasks

• ephemeral feature:

  • setup improvements (currently facing known issues with timeouts)
  • fixup tests in emphermal.yml (api seems to have issues currently though)

• check and potentially update other third party actions

  • replace github-actions versions with the actual hash to prevent supply chain attacks (following-up on Pin the the jenseng/dynamic-uses transitive GH Action dependency to a hash #48, where we already did this, but just for one action so far)

[github-actions]

⚡️ Running CI build with LocalStack ...

[steffyP]

Q: is that the right way to do it? Happy to change it back, but I guess as we have the action in the organization it makes more sense to use "LocalStack"?

[alexrashed]

Yes, looks good to me! Imho this is only there for historical reasons, the action was handed over from @HarshCasper early after the initial creation. However, maybe we could just adjust it according to @HarshCasper's directions in a follow up.

[alexrashed]

Nice! The action is getting cleaner and cleaner with every PR! The changes here are looking good to me!
However, you mentioned in the PR description that this PR should contain some GitHub action digest updates, even though I couldn't see them in the changeset. Has this been superseded, or did I miss it? :)

[alexrashed]

Yes, looks good to me! Imho this is only there for historical reasons, the action was handed over from @HarshCasper early after the initial creation. However, maybe we could just adjust it according to @HarshCasper's directions in a follow up.

[steffyP]

However, you mentioned in the PR description that this PR should contain some GitHub action digest updates, even though I couldn't see them in the changeset. Has this been superseded, or did I miss it? :)

I updated the description a couple of times to reflect the actual changes, maybe it was an outdated description version?

It's currently listed under "followup tasks": check and potentially update other third party actions.
So expect another PR soon 😅 I thought it would be cleaner this way.