Composable actions for linting manifest PR

[chawyehsu]

New actions should be stored under a subfolder, so downstreams can use it composably by referring uses: ScoopInstall/GithubActions/<subfolder>@<sha1>

Lint PR title

The following conventions to be followed:

• https://github.com/ScoopInstaller/.github/blob/main/.github/CONTRIBUTING.md#for-scoop-buckets
• https://github.com/ScoopInstaller/Main/blob/master/.github/pull_request_template.md?plain=1#L21
  • <manifest-name[@version]|\(chore\)>: <General summary of the pull request>
• parenthetical portion (*) can appear as part of the <manifest> section ONLY when the diff of one PR involves multiple manifests
  • parenthetical portion supports wildcard (*) or specific chars e.g. app-name(-beta), where the symbol rules also apply to.

Reference for similar implementation approaches: https://github.com/chawyehsu/actions/tree/main/semantic-pr-title

Other linting rules to consider

• A manifest MUST be placed in the bucket subfolder of the bucket repository
  • (OPTION) or the nested subfolder of bucket folder
• The name of a manifest MUST use lowercase letters, numbers, dots (.) and hyphens (-) only, and MUST NOT start with hyphens (-) and dots (.), and MUST NOT end with dots (.)
• The fields in a manifest SHOULD follow the general order defined in https://github.com/ScoopInstaller/.github/blob/main/.github/CONTRIBUTING.md#for-scoop-buckets

[z-Fng]

• The fields in a manifest SHOULD follow the general order defined in https://github.com/ScoopInstaller/.github/blob/main/.github/CONTRIBUTING.md#for-scoop-buckets

As a side note, a simple lint check (#61) was introduced earlier to detect issues like incorrect indentation and single-element arrays. The implementation is pretty straightforward - it compares the raw file content with the output from formatjson.ps1, and fails the check if they don't match. We actually wanted to expand formatjson.ps1 (ScoopInstaller/Scoop#6494) so it could sort keys in JSON files, allowing contributors to handle all formatting by running the script once. However, ScoopInstaller/Scoop#6494 was put on hold due to disagreements over how it should be implemented. 😅