Bump rambulance from 0.5.0 to 0.6.0

Bumps [rambulance](https://github.com/yuki24/rambulance) from 0.5.0 to 0.6.0.
- [Release notes](https://github.com/yuki24/rambulance/releases)
- [Changelog](https://github.com/yuki24/rambulance/blob/master/CHANGELOG.md)
- [Commits](yuki24/rambulance@v0.5.0...v0.6.0)

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

Gemfile.lock

@@ -103,7 +103,7 @@ GEM
     dotenv-rails (2.2.1)
       dotenv (= 2.2.1)
       railties (>= 3.2, < 5.2)
-    erubi (1.7.0)
+    erubi (1.7.1)
     exception_notification (4.2.2)
       actionmailer (>= 4.0, < 6)
       activesupport (>= 4.0, < 6)
@@ -257,7 +257,7 @@ GEM
       rake (>= 0.8.7)
       thor (>= 0.18.1, < 2.0)
     rake (12.3.0)
-    rambulance (0.5.0)
+    rambulance (0.6.0)
       actionpack
       activesupport
       railties