Upgrade default build to use java 17

Building with an older version of java will not allow the plugin to run
on a default Gerrit 3.9 war build, so upgrade the plugin to build with
the Gerrit 3.9 plugin api which will make it build the plugin with java
17 and be able to do so. Building with java 17 will prevent this from
being run on older default war builds.

Change-Id: I6b84d8099b3fab534bfcd436a01f4bb53d72d50e
2 files changed