Update plugin

Pull in git updates for plugin {RepoName}: the checked-out branch's tip, or, when the versions[] entry for this FPP pins a sha the clone has not passed, that sha and no further. Before the plugin's own fpp_upgrade.sh (or fpp_install.sh) runs, its declared dependencies are reconciled against the new version: newly declared apt, Python and script dependencies are installed, and package claims the new version no longer declares are released (apt-removed once nothing else needs them). A newly declared dependency plugin is reported, not installed -- the operator has to see its privacy disclosure on the Plugins page. Supports ?stream=true.