Version bump for 4.21

Needed by
https://git.eclipse.org/r/c/platform/eclipse.platform.debug/+/172237

Change-Id: I3792168701bc52e60cc5e9a470dc2ba5bce34129
Signed-off-by: Alexander Kurtakov <akurtako@redhat.com>
Reviewed-on: https://git.eclipse.org/r/c/platform/eclipse.platform.debug/+/183213
Tested-by: Platform Bot <platform-bot@eclipse.org>
1 file changed