bump rubygems

Gemfile.lock

@@ -7,7 +7,7 @@ GEM
       cucumber (>= 2.4, < 6.0)
       rspec-expectations (~> 3.4)
       thor (~> 1.0)
-    backports (3.23.0)
+    backports (3.24.1)
     builder (3.2.4)
     childprocess (4.1.0)
     contracts (0.16.1)
@@ -30,24 +30,24 @@ GEM
     diff-lcs (1.5.0)
     gherkin (5.1.0)
     multi_json (1.15.0)
-    multi_test (0.1.2)
-    mustermann (2.0.2)
+    multi_test (1.1.0)
+    mustermann (3.0.0)
       ruby2_keywords (~> 0.0.1)
-    rack (2.2.4)
-    rack-protection (2.2.3)
-      rack
-    rspec-expectations (3.11.0)
+    rack (2.2.8)
+    rack-protection (3.1.0)
+      rack (~> 2.2, >= 2.2.4)
+    rspec-expectations (3.12.3)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.11.0)
-    rspec-support (3.11.0)
+      rspec-support (~> 3.12.0)
+    rspec-support (3.12.1)
     ruby2_keywords (0.0.5)
-    sinatra (2.2.3)
-      mustermann (~> 2.0)
-      rack (~> 2.2)
-      rack-protection (= 2.2.3)
+    sinatra (3.1.0)
+      mustermann (~> 3.0)
+      rack (~> 2.2, >= 2.2.4)
+      rack-protection (= 3.1.0)
       tilt (~> 2.0)
-    thor (1.2.1)
-    tilt (2.0.11)
+    thor (1.2.2)
+    tilt (2.3.0)
 
 PLATFORMS
   java