Upgrade git-commit-id-plugin to 4.9.0 and set useNativeGit to not fail on git worktrees

[groldan]

jgit does not support git worktrees. Setting the config option <useNativeGit>true</useNativeGit> makes it not fail.

[aaime]

+1.
It would be nice to have the same configuration across the board. Right now GT is using the same version as GWC, while GeoServer is already on 4.9 but the native git is left as an exercise for the reader, with instructions on how to set up the settings.xml in .m2.... any issue in having it on all the time?

[groldan]

In GeoServer one has to run maven with -Dgit.commit.useNative=true. It'd be nice if it was the default. I'm not sure how many devs use worktrees, but I use them all the time. In any case, whomever is trying to run a build, most probably have native git installed, though I'm not sure if the plugin would fall back to jgit when it's not?