Bump json from 2.1.0 to 2.3.1 (#69)

Bumps [json](https://github.com/flori/json) from 2.1.0 to 2.3.1.
- [Release notes](https://github.com/flori/json/releases)
- [Changelog](https://github.com/flori/json/blob/master/CHANGES.md)
- [Commits](ruby/json@v2.1.0...v2.3.1)

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

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

Author: dependabot[bot]

Gemfile.lock

@@ -18,7 +18,7 @@ GEM
     diff-lcs (1.3)
     docile (1.3.1)
     ffi (1.13.1)
-    json (2.1.0)
+    json (2.3.1)
     rake (12.3.3)
     rgeo (2.1.1)
     rgeo-geojson (2.1.1)