Allow Slim to be used with Tilt 2.1.0 (#910)

It would be great to be able to use Slim with Tilt 2.1.0
https://github.com/jeremyevans/tilt/blob/7907334d43afb53d37122470e5b346d235ad40c2/CHANGELOG.md#210-2023-02-17

Author: dentarg

slim.gemspec

@@ -19,5 +19,5 @@ Gem::Specification.new do |s|
   s.required_ruby_version = '>= 2.5.0'
 
   s.add_runtime_dependency('temple', ['~> 0.10.0'])
-  s.add_runtime_dependency('tilt', ['>= 2.0.6', '< 2.1'])
+  s.add_runtime_dependency('tilt', ['>= 2.0.6', '< 2.2'])
 end