Bump @actions/core from 1.6.0 to 1.9.1 (#5)

Bumps [@actions/core](https://github.com/actions/toolkit/tree/HEAD/packages/core) from 1.6.0 to 1.9.1.
- [Release notes](https://github.com/actions/toolkit/releases)
- [Changelog](https://github.com/actions/toolkit/blob/main/packages/core/RELEASES.md)
- [Commits](https://github.com/actions/toolkit/commits/HEAD/packages/core)

---
updated-dependencies:
- dependency-name: "@actions/core"
  dependency-type: direct:production
...

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Author: dependabot[bot]

package-lock.json

@@ -20,7 +20,7 @@
   "author": "Florian Fittschen",
   "license": "MIT",
   "dependencies": {
-    "@actions/core": "^1.2.6",
+    "@actions/core": "^1.9.1",
     "@actions/github": "^4.0.0",
     "@slack/web-api": "^6.10.0"
   },