Bug 573962 - Update product version number to 4.21 across build script

Change-Id: Ia60c93f54b17842ab1f37039b67e2c9102a11e62
Signed-off-by: Sravan Kumar Lakkimsetti <sravankumarl@in.ibm.com>
Reviewed-on: https://git.eclipse.org/r/c/equinox/rt.equinox.p2/+/181362
1 file changed