Increase Java heap size for running Maven in Dockerfile of branch-2.10

$ ./dev-support/bin/create-release --docker --dockercache --native
$ tail -n 5 patchprocess/mvn_install.log
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 07:06 min
Exception in thread "main"
Exception: java.lang.OutOfMemoryError thrown from the UncaughtExceptionHandler in thread "main"