fix(deps): remove ajv as dependency (#248)

* fix(deps): bump ajv from 5.5.2 to 6.12.4

Bumps [ajv](https://github.com/ajv-validator/ajv) from 5.5.2 to 6.12.4.
- [Release notes](https://github.com/ajv-validator/ajv/releases)
- [Commits](ajv-validator/ajv@v5.5.2...v6.12.4)

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

* chore(deps): remove ajv as dependency

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Antariksh Mahajan <antarikshmahajan@gmail.com>

package.json

@@ -69,7 +69,6 @@
     "@opengovsg/spcp-auth-client": "^1.3.0",
     "@stablelib/base64": "^1.0.0",
     "JSONStream": "^1.3.5",
-    "ajv": "^5.2.3",
     "angular": "~1.8.0",
     "angular-animate": "^1.8.0",
     "angular-aria": "^1.8.0",