fix: samples/server/petstore/ruby-sinatra/Gemfile & samples/server/petstore/ruby-sinatra/Gemfile.lock to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-RUBY-RACK-13378928
- https://snyk.io/vuln/SNYK-RUBY-RACK-13378930
- https://snyk.io/vuln/SNYK-RUBY-RACK-13378932

Author: snyk-bot

samples/server/petstore/ruby-sinatra/Gemfile

@@ -1,5 +1,5 @@
 source 'https://rubygems.org'
 
 gem "webrick"
-gem "sinatra"
+gem "sinatra", ">= 2.0.0"
 gem "sinatra-cross_origin"

samples/server/petstore/ruby-sinatra/Gemfile.lock

@@ -1,19 +1,37 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    rack (1.6.4)
-    rack-protection (1.5.3)
-      rack
-    sinatra (1.4.6)
-      rack (~> 1.4)
-      rack-protection (~> 1.4)
-      tilt (>= 1.3, < 3)
+    base64 (0.3.0)
+    logger (1.7.0)
+    mustermann (3.0.4)
+      ruby2_keywords (~> 0.0.1)
+    rack (3.2.2)
+    rack-protection (4.2.0)
+      base64 (>= 0.1.0)
+      logger (>= 1.6.0)
+      rack (>= 3.0.0, < 4)
+    rack-session (2.1.1)
+      base64 (>= 0.1.0)
+      rack (>= 3.0.0)
+    ruby2_keywords (0.0.5)
+    sinatra (4.2.0)
+      logger (>= 1.6.0)
+      mustermann (~> 3.0)
+      rack (>= 3.0.0, < 4)
+      rack-protection (= 4.2.0)
+      rack-session (>= 2.0.0, < 3)
+      tilt (~> 2.0)
     sinatra-cross_origin (0.3.2)
-    tilt (2.0.1)
+    tilt (2.6.1)
+    webrick (1.9.1)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
-  sinatra
+  sinatra (>= 2.0.0)
   sinatra-cross_origin
+  webrick
+
+BUNDLED WITH
+   2.3.27