prepare for next development iteration (3.2.1)
backport: fix postgres validation query (MARMOTTA-498)

(cherry picked from commit dfde1a8ea61dbbd43318af63b7278d42beddc38d)
Signed-off-by: Jakob Frank <jakob@apache.org>
[maven-release-plugin] prepare release 3.2.1
Merge master into develop
Merge remote-tracking branch 'origin/develop' into develop