Use https instead.

Change-Id: I31a7836c664f429450f8e826dc62c1e031f125e9
Signed-off-by: Alexander Kurtakov <akurtako@redhat.com>
Reviewed-on: https://git.eclipse.org/r/c/platform/eclipse.platform.ui/+/190660
Tested-by: Platform Bot <platform-bot@eclipse.org>