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 cfe2e55..7a55dc7 100644
--- a/project.config
+++ b/project.config
@@ -12,6 +12,6 @@
 	submit = group github/openbmc/autotest-maintainers
 	editTopicName = group github/openbmc/autotest-maintainers
 [access "refs/tags/*"]
-	pushTag = +force group github/openbmc/autotest-maintainers
+	pushTag = group github/openbmc/autotest-maintainers
 	pushSignedTag = group github/openbmc/autotest-maintainers
 	push = +force group github/openbmc/autotest-maintainers