Advice should suggest adding `pages: read` for private repositories

[jsoref]

Error: Get Pages site failed. Please verify that the repository has Pages enabled and configured to build using GitHub Actions, or consider exploring the enablement parameter for this action. Error: Resource not accessible by integration - https://docs.github.com/rest/pages/pages#get-a-apiname-pages-site
Error: HttpError: Resource not accessible by integration - https://docs.github.com/rest/pages/pages#get-a-apiname-pages-site

GitHub workflows+actions can determine if the repository for which they're running is private (jq -r '.repository.private // empty' "$GITHUB_EVENT_PATH" == true) and this action should check that and suggest adding:

permissions:
  pages: read

instead of just suggesting that the repository needs "Pages enabled" "and configured to build using GitHub actions" or whatever an enablement is.

configure-pages/action.yml

Lines 18 to 21 in d560657

	enablement:
	description: 'Try to enable Pages for the repository if it is not already enabled. This option requires a token other than `GITHUB_TOKEN` to be provided. In the context of a Personal Access Token, the `repo` scope or Pages write permission is required. In the context of a GitHub App, the `administration:write` and `pages:write` permissions are required.'
	default: 'false'
	required: false