ci: Only publish draft spec from main branch
ci: Only publish draft spec from main branch

We don't want release branch builds overwriting the drafts specs built
in the main branch.

Signed-off-by: BJ Hargrave <79c2611307ec26eadfef14d3896a4f8c046a371e@us.ibm.com>

osgi/osgi,osgi/osgi,osgi/osgi,osgi/osgi,osgi/osgi,osgi/osgi,osgi/osgi,osgi/osgi