chore(deps): update dependency sinatra to v2.2.0 [security]

Gemfile.lock

@@ -49,7 +49,8 @@ GEM
     mini_portile2 (2.8.0)
     minitest (5.14.4)
     multi_json (1.13.1)
-    mustermann (1.0.3)
+    mustermann (1.1.1)
+      ruby2_keywords (~> 0.0.1)
     net-sftp (3.0.0.beta1)
       net-ssh (>= 5.0.0, < 6.0.0)
     net-ssh (5.2.0)
@@ -77,6 +78,7 @@ GEM
     rb-inotify (0.10.0)
       ffi (~> 1.0)
     rr (1.2.1)
+    ruby2_keywords (0.0.5)
     sass (3.7.4)
       sass-listen (~> 4.0.0)
     sass-listen (4.0.0)