fix(ci): Remove submodule once and for all (#15495)

Signed-off-by: Christian Haudum <christian.haudum@gmail.com>

Author: chaudum

.gitignore

@@ -36,6 +36,9 @@ dist
 pkg/loki/wal
 tools/lambda-promtail/main
 
+# Submodule added by `act` CLI
+_shared-workflows-dockerhub-login
+
 # Workspaces
 *.work
 *.work.sum