Bump ajv from 6.12.6 to 8.12.0

Bumps [ajv](https://github.com/ajv-validator/ajv) from 6.12.6 to 8.12.0.
- [Release notes](https://github.com/ajv-validator/ajv/releases)
- [Commits](ajv-validator/ajv@v6.12.6...v8.12.0)

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

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

Author: dependabot[bot]

package.json

@@ -45,7 +45,7 @@
         "url": "https://github.com/DeMaCS-UNICAL/LoIDE/issues"
     },
     "dependencies": {
-        "ajv": "^6.12.6",
+        "ajv": "^8.12.0",
         "compression": "^1.7.3",
         "express": "^4.18.1",
         "express-force-ssl": "^0.3.2",