chore: use new sign script

Author: simPod

package.json

@@ -10,6 +10,7 @@
     "lint:fix": "yarn run lint --fix",
     "prettier:check": "prettier --list-different \"**/*.{ts,tsx,scss}\"",
     "prettier:write": "yarn run prettier:check --write",
+    "sign": "npx --yes @grafana/sign-plugin@latest",
     "test": "jest --watch --onlyChanged",
     "test:ci": "jest --passWithNoTests --maxWorkers 4",
     "typecheck": "tsc --noEmit"