Bump sinatra from 2.0.8.1 to 2.1.0

Bumps [sinatra](https://github.com/sinatra/sinatra) from 2.0.8.1 to 2.1.0.
- [Release notes](https://github.com/sinatra/sinatra/releases)
- [Changelog](https://github.com/sinatra/sinatra/blob/master/CHANGELOG.md)
- [Commits](sinatra/sinatra@v2.0.8.1...v2.1.0)

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

Gemfile.lock

@@ -14,7 +14,6 @@ GEM
       tzinfo (~> 1.1)
     addressable (2.7.0)
       public_suffix (>= 2.0.2, < 5.0)
-    backports (3.18.1)
     builder (3.2.4)
     concurrent-ruby (1.1.6)
     cookiejar (0.3.3)
@@ -75,7 +74,7 @@ GEM
       mail (>= 2.0)
     public_suffix (4.0.5)
     rack (2.2.3)
-    rack-protection (2.0.8.1)
+    rack-protection (2.1.0)
       rack
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -102,17 +101,16 @@ GEM
       json (>= 1.8, < 3)
       simplecov-html (~> 0.10.0)
     simplecov-html (0.10.2)
-    sinatra (2.0.8.1)
+    sinatra (2.1.0)
       mustermann (~> 1.0)
-      rack (~> 2.0)
-      rack-protection (= 2.0.8.1)
+      rack (~> 2.2)
+      rack-protection (= 2.1.0)
       tilt (~> 2.0)
-    sinatra-contrib (2.0.8.1)
-      backports (>= 2.8.2)
+    sinatra-contrib (2.1.0)
       multi_json
       mustermann (~> 1.0)
-      rack-protection (= 2.0.8.1)
-      sinatra (= 2.0.8.1)
+      rack-protection (= 2.1.0)
+      sinatra (= 2.1.0)
       tilt (~> 2.0)
     sync (0.5.0)
     term-ansicolor (1.7.1)