Remove force option from 'Push Annotated Tag' permission

The force option on 'Push Annotated Tag' had no effect and is no longer
supported.
diff --git a/project.config b/project.config
index a398f8c..273d306 100644
--- a/project.config
+++ b/project.config
@@ -13,6 +13,6 @@
 	submit = group github/openbmc/bitbake-maintainers
 	editTopicName = group github/openbmc/bitbake-maintainers
 [access "refs/tags/*"]
-	pushTag = +force group github/openbmc/bitbake-maintainers
+	pushTag = group github/openbmc/bitbake-maintainers
 	pushSignedTag = group github/openbmc/bitbake-maintainers
 	push = +force group github/openbmc/bitbake-maintainers