ci: explicit actions permissions

[ricellis]

PR summary

Explicit include of only necessary permissions for actions token.

Fixes: part of s1014

Note: An existing issue is required before opening a PR.

PR Checklist

Please make sure that your PR fulfills the following requirements:

• The commit message follows the
  Angular Commit Message Guidelines.
• Tests for the changes have been added (for bug fixes / features) - N/A
• Docs have been added / updated (for bug fixes / features) - N/A

PR Type

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• New tests
• Build/CI related changes
• Documentation content changes
• Other (please describe)

What is the current behavior?

Default restrictive token is applied.

What is the new behavior?

permissions: {}
Give the token no additional permissions (the empty set includes metadata: read which is always given).
content: read should not be needed even for checkout since it is a public repository.

Does this PR introduce a breaking change?

• Yes
• No

Other information