Bump sinatra in /api/ruby/building-your-first-github-app

Bumps [sinatra](https://github.com/sinatra/sinatra) from 2.0.3 to 2.2.3.
- [Release notes](https://github.com/sinatra/sinatra/releases)
- [Changelog](https://github.com/sinatra/sinatra/blob/master/CHANGELOG.md)
- [Commits](sinatra/sinatra@v2.0.3...v2.2.3)

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

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

Author: dependabot[bot]

api/ruby/building-your-first-github-app/Gemfile

@@ -2,4 +2,4 @@ source "https://rubygems.org"
 
 gem "jwt", "~> 2.1"
 gem "octokit", "~> 4.0"
-gem "sinatra", "~> 2.0"
+gem "sinatra", "~> 2.2"

api/ruby/building-your-first-github-app/Gemfile.lock

@@ -7,30 +7,32 @@ GEM
       multipart-post (>= 1.2, < 3)
     jwt (2.1.0)
     multipart-post (2.0.0)
-    mustermann (1.0.2)
+    mustermann (2.0.2)
+      ruby2_keywords (~> 0.0.1)
     octokit (4.9.0)
       sawyer (~> 0.8.0, >= 0.5.3)
     public_suffix (3.0.2)
     rack (2.2.6.2)
-    rack-protection (2.0.3)
+    rack-protection (2.2.3)
       rack
+    ruby2_keywords (0.0.5)
     sawyer (0.8.1)
       addressable (>= 2.3.5, < 2.6)
       faraday (~> 0.8, < 1.0)
-    sinatra (2.0.3)
-      mustermann (~> 1.0)
-      rack (~> 2.0)
-      rack-protection (= 2.0.3)
+    sinatra (2.2.3)
+      mustermann (~> 2.0)
+      rack (~> 2.2)
+      rack-protection (= 2.2.3)
       tilt (~> 2.0)
-    tilt (2.0.8)
+    tilt (2.1.0)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
   jwt (~> 2.1)
   octokit (~> 4.0)
-  sinatra (~> 2.0)
+  sinatra (~> 2.2)
 
 BUNDLED WITH
    1.14.6