Bump ajv from 6.12.0 to 6.12.3 in /envkey-electron

Bumps [ajv](https://github.com/ajv-validator/ajv) from 6.12.0 to 6.12.3.
- [Release notes](https://github.com/ajv-validator/ajv/releases)
- [Commits](ajv-validator/ajv@v6.12.0...v6.12.3)

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

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

envkey-electron/package.json

@@ -56,7 +56,7 @@
     "electron-store": "^1.3.0"
   },
   "devDependencies": {
-    "ajv": "^6.9.1",
+    "ajv": "^6.12.3",
     "electron": "^4.2.12",
     "electron-builder": "^22.4.1",
     "electron-builder-squirrel-windows": "^22.4.1",