build(deps): bump @actions/core in /.github/actions/send-email (#1878)

Author: dependabot[bot]

.github/actions/send-email/package-lock.json

@@ -14,7 +14,7 @@
   "author": "Firebase <[email protected]> (https://firebase.google.com/)",
   "license": "Apache-2.0",
   "dependencies": {
-    "@actions/core": "^1.2.6",
+    "@actions/core": "^1.9.1",
     "mailgun.js": "^3.3.0"
   },
   "devDependencies": {