Bump faraday from 0.15.3 to 0.15.4

Bumps [faraday](https://github.com/lostisland/faraday) from 0.15.3 to 0.15.4.
- [Release notes](https://github.com/lostisland/faraday/releases)
- [Changelog](https://github.com/lostisland/faraday/blob/master/CHANGELOG.md)
- [Commits](lostisland/faraday@v0.15.3...v0.15.4)

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

Author: dependabot-support

Gemfile.lock

@@ -26,7 +26,7 @@ GEM
       ffi (>= 1.3.0)
     eventmachine (1.2.7)
     execjs (2.7.0)
-    faraday (0.15.3)
+    faraday (0.15.4)
       multipart-post (>= 1.2, < 3)
     ffi (1.9.25)
     forwardable-extended (2.6.0)