Bump @actions/core from 1.3.0 to 1.4.0

Bumps [@actions/core](https://github.com/actions/toolkit/tree/HEAD/packages/core) from 1.3.0 to 1.4.0.
- [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
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -19,7 +19,7 @@
   },
   "homepage": "https://github.com/DavideViolante/sprint-milestone-action#readme",
   "dependencies": {
-    "@actions/core": "^1.3.0",
+    "@actions/core": "^1.4.0",
     "axios": "^0.21.1",
     "moment": "^2.29.1"
   },