Bump sinatra from 1.4.8 to 2.2.0

Bumps [sinatra](https://github.com/sinatra/sinatra) from 1.4.8 to 2.2.0.
- [Release notes](https://github.com/sinatra/sinatra/releases)
- [Changelog](https://github.com/sinatra/sinatra/blob/master/CHANGELOG.md)
- [Commits](sinatra/sinatra@v1.4.8...v2.2.0)

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

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

Author: dependabot[bot]

Gemfile.lock

@@ -54,6 +54,8 @@ GEM
     method_source (0.8.2)
     minitest (5.14.1)
     multipart-post (2.0.0)
+    mustermann (1.1.1)
+      ruby2_keywords (~> 0.0.1)
     nio4r (2.0.0)
     pry (0.10.4)
       coderay (~> 1.1.0)
@@ -64,8 +66,8 @@ GEM
       pry (~> 0.10)
     public_suffix (2.0.5)
     puma (3.12.6)
-    rack (1.6.13)
-    rack-protection (1.5.5)
+    rack (2.2.3)
+    rack-protection (2.2.0)
       rack
     rack-test (0.6.3)
       rack (>= 1.0)
@@ -83,11 +85,13 @@ GEM
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.5.0)
     rspec-support (3.5.0)
+    ruby2_keywords (0.0.5)
     safe_yaml (1.0.4)
-    sinatra (1.4.8)
-      rack (~> 1.5)
-      rack-protection (~> 1.4)
-      tilt (>= 1.3, < 3)
+    sinatra (2.2.0)
+      mustermann (~> 1.0)
+      rack (~> 2.2)
+      rack-protection (= 2.2.0)
+      tilt (~> 2.0)
     slack-ruby-bot (0.10.1)
       hashie
       slack-ruby-client (>= 0.6.0)
@@ -102,7 +106,7 @@ GEM
     slop (3.6.0)
     thor (0.19.4)
     thread_safe (0.3.6)
-    tilt (2.0.7)
+    tilt (2.0.10)
     timers (4.1.2)
       hitimes
     tzinfo (1.2.7)