build(deps): bump openpgp from 5.3.0 to 5.4.0 (#799)

Bumps [openpgp](https://github.com/openpgpjs/openpgpjs) from 5.3.0 to 5.4.0.
- [Release notes](https://github.com/openpgpjs/openpgpjs/releases)
- [Commits](openpgpjs/openpgpjs@v5.3.0...v5.4.0)

---
updated-dependencies:
- dependency-name: openpgp
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

package.json

@@ -27,7 +27,7 @@
     "@actions/exec": "^1.1.1",
     "@actions/github": "^5.0.3",
     "node-fetch": "^3.2.4",
-    "openpgp": "5.3"
+    "openpgp": "5.4"
   },
   "devDependencies": {
     "@types/jest": "^27.5.0",