Bump json_schemer from 0.2.19 to 0.2.20

Bumps [json_schemer](https://github.com/davishmcclurg/json_schemer) from 0.2.19 to 0.2.20.
- [Release notes](https://github.com/davishmcclurg/json_schemer/releases)
- [Commits](https://github.com/davishmcclurg/json_schemer/compare/v0.2.19...v0.2.20)

---
updated-dependencies:
- dependency-name: json_schemer
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Gemfile.lock

@@ -215,7 +215,7 @@ GEM
     js-routes (2.2.3)
       railties (>= 4)
     json (2.6.1)
-    json_schemer (0.2.19)
+    json_schemer (0.2.20)
       ecma-re-validator (~> 0.3)
       hana (~> 1.3)
       regexp_parser (~> 2.0)