Bump ajv from 5.2.5 to 6.12.3 in /ACEs/aces-pnp-property-controls

Bumps [ajv](https://github.com/ajv-validator/ajv) from 5.2.5 to 6.12.3.
- [Release notes](https://github.com/ajv-validator/ajv/releases)
- [Commits](ajv-validator/ajv@v5.2.5...v6.12.3)

---
updated-dependencies:
- dependency-name: ajv
  dependency-type: direct:development
...

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Author: dependabot[bot]

ACEs/aces-pnp-property-controls/package-lock.json

@@ -20,7 +20,7 @@
     "@microsoft/sp-module-interfaces": "1.13.0",
     "@microsoft/rush-stack-compiler-3.9": "0.4.47",
     "gulp": "~4.0.2",
-    "ajv": "~5.2.2",
+    "ajv": "~6.12.3",
     "@types/webpack-env": "1.13.1"
   }
 }