Function pick_open_pr 

pub fn pick_open_pr(json: &str, base: &str) -> Result<OpenPr>

Pure half of find_open_pr: classify the raw --json number,url,title,baseRefName output. Entries whose base is not base are dropped even though the query already filtered on it, so a stub or an old gh that ignores --base cannot get a pull request into the wrong branch adopted.