Bump execa from 5.1.1 to 9.5.1

Bumps [execa](https://github.com/sindresorhus/execa) from 5.1.1 to 9.5.1.
- [Release notes](https://github.com/sindresorhus/execa/releases)
- [Commits](sindresorhus/execa@v5.1.1...v9.5.1)

---
updated-dependencies:
- dependency-name: execa
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

package.json

@@ -70,7 +70,7 @@
     "ember-tether": "^3.1.0",
     "ember-truth-helpers": "^4.0.3",
     "esm": "^3.2.25",
-    "execa": "5.1.1",
+    "execa": "9.5.1",
     "fs-extra": "^11.2.0",
     "git-repo-info": "^2.1.1",
     "highlight.js": "^11.10.0",