Bump json5 and ava

Removes [json5](https://github.com/json5/json5). It's no longer used after updating ancestor dependency [ava](https://github.com/avajs/ava). These dependencies need to be updated together.


Removes `json5`

Updates `ava` from 0.25.0 to 5.1.1
- [Release notes](https://github.com/avajs/ava/releases)
- [Commits](https://github.com/avajs/ava/compare/v0.25.0...v5.1.1)

---
updated-dependencies:
- dependency-name: json5
  dependency-type: indirect
- dependency-name: ava
  dependency-type: direct:development
...

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

package.json

@@ -22,7 +22,7 @@
     "randombytes": "^2.0.6"
   },
   "devDependencies": {
-    "ava": "^0.25.0",
+    "ava": "^5.1.1",
     "coveralls": "^3.0.2",
     "nyc": "^13.1.0",
     "xo": "^0.23.0"