Bump ajv from 8.14.0 to 8.15.0 (#1578)

Bumps [ajv](https://github.com/ajv-validator/ajv) from 8.14.0 to 8.15.0.
- [Release notes](https://github.com/ajv-validator/ajv/releases)
- [Commits](ajv-validator/ajv@v8.14.0...v8.15.0)

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

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

package.json

@@ -32,7 +32,7 @@
   "main": "index.js",
   "bin": "./reffy.js",
   "dependencies": {
-    "ajv": "8.14.0",
+    "ajv": "8.15.0",
     "ajv-formats": "3.0.1",
     "commander": "12.1.0",
     "fetch-filecache-for-crawling": "5.1.1",