Update Tycho pomless to 2.6.0

Change-Id: I71688c233b4da8f56b477e4989ba137a1a57c888
Reviewed-on: https://git.eclipse.org/r/c/platform/eclipse.platform.resources/+/189873
Tested-by: Platform Bot <platform-bot@eclipse.org>
Reviewed-by: Alexander Kurtakov <akurtako@redhat.com>
1 file changed