Bug 553037 - Fails to compile with Java 11

Use maven.compiler.release option that's added in Tycho 1.6.0-SNAPSHOT
to say which version to compile against.
This will make maven compile fail when run on Java 8 but it's a fine
workaround now that we expect to be building with Java 11.

Change-Id: I9fc18d1b123a32b86639301c8c77184ed7ad4cde
Signed-off-by: Alexander Kurtakov <akurtako@redhat.com>
2 files changed