pxygithubpxy rule mirror

GET /gh/{owner}/{repo}@{ref}/{path}          raw.githubusercontent.com, falls back to jsdelivr
GET /raw/{owner}/{repo}/{ref}/{path}         raw.githubusercontent.com
GET /releases/{owner}/{repo}/{tag}/{file}    GitHub release asset
GET /codeload/{owner}/{repo}/zip/refs/heads/{branch}  codeload.github.com
GET /https://{allowed-host}/{path}           absolute form, allowlisted hosts only