Bump sinatra from 2.2.0 to 2.2.3

Bumps [sinatra](https://github.com/sinatra/sinatra) from 2.2.0 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@v2.2.0...v2.2.3)

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

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

Author: dependabot[bot]

Gemfile

@@ -1,5 +1,5 @@
 source 'https://rubygems.org'
 ruby '2.5.3'
 
-gem 'sinatra', '~>2.2.0'
+gem 'sinatra', '~>2.2.3'
 gem 'json'

Gemfile.lock

@@ -2,25 +2,25 @@ GEM
   remote: https://rubygems.org/
   specs:
     json (2.3.0)
-    mustermann (1.1.1)
+    mustermann (2.0.2)
       ruby2_keywords (~> 0.0.1)
     rack (2.2.4)
-    rack-protection (2.2.0)
+    rack-protection (2.2.3)
       rack
     ruby2_keywords (0.0.5)
-    sinatra (2.2.0)
-      mustermann (~> 1.0)
+    sinatra (2.2.3)
+      mustermann (~> 2.0)
       rack (~> 2.2)
-      rack-protection (= 2.2.0)
+      rack-protection (= 2.2.3)
       tilt (~> 2.0)
-    tilt (2.0.10)
+    tilt (2.0.11)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
   json
-  sinatra (~> 2.2.0)
+  sinatra (~> 2.2.3)
 
 RUBY VERSION
    ruby 2.5.3p105