Bump sinatra from 2.0.0 to 3.0.4

Bumps [sinatra](https://github.com/sinatra/sinatra) from 2.0.0 to 3.0.4.
- [Release notes](https://github.com/sinatra/sinatra/releases)
- [Changelog](https://github.com/sinatra/sinatra/blob/master/CHANGELOG.md)
- [Commits](https://github.com/sinatra/sinatra/compare/v2.0.0...v3.0.4)

---
updated-dependencies:
- dependency-name: sinatra
  dependency-type: direct:production
...

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

Gemfile.lock

@@ -23,7 +23,6 @@ GEM
     aws-sdk-resources (2.10.53)
       aws-sdk-core (= 2.10.53)
     aws-sigv4 (1.0.2)
-    backports (3.8.0)
     bigdecimal (1.3.2)
     capybara (2.15.1)
       addressable
@@ -53,8 +52,9 @@ GEM
     mini_mime (0.1.4)
     mini_portile2 (2.3.0)
     minitest (5.10.3)
-    multi_json (1.12.2)
-    mustermann (1.0.1)
+    multi_json (1.15.0)
+    mustermann (3.0.0)
+      ruby2_keywords (~> 0.0.1)
     nokogiri (1.8.1)
       mini_portile2 (~> 2.3.0)
     poltergeist (1.16.0)
@@ -65,8 +65,8 @@ GEM
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
     public_suffix (3.0.0)
-    rack (2.0.3)
-    rack-protection (2.0.0)
+    rack (2.2.4)
+    rack-protection (3.0.4)
       rack
     rack-test (0.7.0)
       rack (>= 1.0, < 3)
@@ -89,22 +89,22 @@ GEM
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.6.0)
     rspec-support (3.6.0)
+    ruby2_keywords (0.0.5)
     ruby_dep (1.5.0)
-    sinatra (2.0.0)
-      mustermann (~> 1.0)
-      rack (~> 2.0)
-      rack-protection (= 2.0.0)
+    sinatra (3.0.4)
+      mustermann (~> 3.0)
+      rack (~> 2.2, >= 2.2.4)
+      rack-protection (= 3.0.4)
       tilt (~> 2.0)
     sinatra-activerecord (2.0.13)
       activerecord (>= 3.2)
       sinatra (>= 1.0)
-    sinatra-contrib (2.0.0)
-      backports (>= 2.0)
+    sinatra-contrib (3.0.4)
       multi_json
-      mustermann (~> 1.0)
-      rack-protection (= 2.0.0)
-      sinatra (= 2.0.0)
-      tilt (>= 1.3, < 3)
+      mustermann (~> 3.0)
+      rack-protection (= 3.0.4)
+      sinatra (= 3.0.4)
+      tilt (~> 2.0)
     sinatra-flash (0.3.0)
       sinatra (>= 1.0.0)
     slim (3.0.8)
@@ -113,7 +113,7 @@ GEM
     sqlite3 (1.3.13)
     temple (0.8.0)
     thread_safe (0.3.6)
-    tilt (2.0.8)
+    tilt (2.0.11)
     tzinfo (1.2.3)
       thread_safe (~> 0.1)
     tzinfo-data (1.2017.2)