ci: minimal-site: set good_signatures to 0

Do not fail the new check that good_signatures ≤ #pubkeys.

contrib/ci/minimal-site/site.conf

@@ -145,7 +145,7 @@
         -- Have multiple maintainers sign your build and only
         -- accept it when a sufficient number of them have
         -- signed it.
-        good_signatures = 2,
+        good_signatures = 0,
 
         -- List of public keys of maintainers.
         pubkeys = {