Adding link to GitHub doc for different access level options

Signed-off-by: Hendrik Ebbers <[email protected]>

README.md

@@ -156,7 +156,8 @@ teams:
 
 repositories:
  - name: <github_repository_name>
- # Teams with access to the repository
+ # Teams with access to the repository.
+ # See https://docs.github.com/en/organizations/managing-user-access-to-your-organizations-repositories/managing-repository-roles/repository-roles-for-an-organization
  #
  # - Key: GitHub team slug
  # - Value: access level
@@ -166,6 +167,7 @@ repositories:
  <github_team_slug>: write
 
  # External collaborators with access to the repository
+ # See https://docs.github.com/en/organizations/managing-user-access-to-your-organizations-repositories/managing-repository-roles/repository-roles-for-an-organization
  #
  # - Key: GitHub username (case sensitive)
  # - Value: access level