build(deps): bump ajv from 6.10.2 to 6.12.6

Bumps [ajv](https://github.com/ajv-validator/ajv) from 6.10.2 to 6.12.6.
- [Release notes](https://github.com/ajv-validator/ajv/releases)
- [Commits](ajv-validator/ajv@v6.10.2...v6.12.6)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

package-lock.json

@@ -23,7 +23,7 @@
     "@open-rpc/meta-schema": "^1.13.13",
     "@open-rpc/schema-utils-js": "^1.13.0",
     "@use-it/interval": "^0.1.3",
-    "ajv": "^6.10.0",
+    "ajv": "^6.12.6",
     "classnames": "^2.2.6",
     "commander": "^2.20.0",
     "isomorphic-fetch": "^2.2.1",