Bump docker-api from 2.1.0 to 2.2.0

Bumps [docker-api](https://github.com/swipely/docker-api) from 2.1.0 to 2.2.0.
- [Release notes](https://github.com/swipely/docker-api/releases)
- [Commits](https://github.com/swipely/docker-api/compare/v2.1.0...v2.2.0)

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

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

Gemfile.lock

@@ -151,14 +151,14 @@ GEM
     debug_inspector (1.1.0)
     diff-lcs (1.4.4)
     docile (1.4.0)
-    docker-api (2.1.0)
+    docker-api (2.2.0)
       excon (>= 0.47.0)
       multi_json
     domain_name (0.5.20190701)
       unf (>= 0.0.5, < 1.0.0)
     erubi (1.10.0)
     eventmachine (1.2.7)
-    excon (0.83.0)
+    excon (0.84.0)
     factory_bot (6.2.0)
       activesupport (>= 5.0.0)
     factory_bot_rails (6.2.0)