Makefile: update cockpit test/common to 321

322 includes the migration from CDP to BiDi browser automation, and will
require some test changes.

Author: croissanne

Makefile

@@ -93,7 +93,7 @@ machine: bots
 
 # checkout Cockpit's test API; this has no API stability guarantee, so check out a stable tag
 test/common:
-	git fetch --depth=1 https://github.com/cockpit-project/cockpit.git 290+chromium-sizzle
+	git fetch --depth=1 https://github.com/cockpit-project/cockpit.git 321
 	git checkout --force FETCH_HEAD -- test/common
 	git reset test/common