Fix mysql localhost quirk.

Idiot, don't you know that 'localhost' means connect to a socket instead?

Author: gwillz

.github/workflows/ci.yml

@@ -89,6 +89,6 @@ jobs:
         configuration: phpunit.xml
         args: '--testdox'
       env:
-        SITES_DB_HOSTNAME: localhost
+        SITES_DB_HOSTNAME: 127.0.0.1
         SITES_POSTGRES_HOSTNAME: localhost
         SITES_REDIS_HOSTNAME: localhost