Bump sinatra from 1.4.6 to 2.2.3

Bumps [sinatra](https://github.com/sinatra/sinatra) from 1.4.6 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@v1.4.6...v2.2.3)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

Gemfile.lock

@@ -9,17 +9,21 @@ GEM
       basiccache (~> 1.0.0)
       nokogiri (~> 1.10.8)
     mini_portile2 (2.4.0)
+    mustermann (2.0.2)
+      ruby2_keywords (~> 0.0.1)
     nokogiri (1.10.10)
       mini_portile2 (~> 2.4.0)
-    rack (1.6.4)
-    rack-protection (1.5.3)
+    rack (2.2.4)
+    rack-protection (2.2.3)
       rack
-    sinatra (1.4.6)
-      rack (~> 1.4)
-      rack-protection (~> 1.4)
-      tilt (>= 1.3, < 3)
+    ruby2_keywords (0.0.5)
+    sinatra (2.2.3)
+      mustermann (~> 2.0)
+      rack (~> 2.2)
+      rack-protection (= 2.2.3)
+      tilt (~> 2.0)
     svgplot (1.0.0)
-    tilt (2.0.1)
+    tilt (2.0.11)
 
 PLATFORMS
   ruby