add env var to disable signups

cluster/apps/vaultwarden/vaultwarden.yml

@@ -19,6 +19,9 @@ spec:
         image: vaultwarden/server:1.34.1
         ports:
         - containerPort: 80
+        env:
+        - name: SIGNUPS_ALLOWED
+          value: "false"
         volumeMounts:
         - name: data
           mountPath: /data/
@@ -26,4 +29,3 @@ spec:
       - name: data
         persistentVolumeClaim:
           claimName: longhorn-vw
-