Upgrade ruby-lsp requirement to v0.21.2 (#502)

Bump our requirement so that we can use the fixes to window show message and the progress additions.

Gemfile.lock

@@ -2,7 +2,7 @@ PATH
   remote: .
   specs:
     ruby-lsp-rails (0.3.21)
-      ruby-lsp (>= 0.21.0, < 0.22.0)
+      ruby-lsp (>= 0.21.2, < 0.22.0)
 
 GEM
   remote: https://rubygems.org/
@@ -224,7 +224,7 @@ GEM
       rubocop (~> 1.51)
     rubocop-sorbet (0.8.3)
       rubocop (>= 0.90.0)
-    ruby-lsp (0.21.0)
+    ruby-lsp (0.21.2)
       language_server-protocol (~> 3.17.0)
       prism (>= 1.2, < 2.0)
       rbs (>= 3, < 4)

ruby-lsp-rails.gemspec

@@ -24,5 +24,5 @@ Gem::Specification.new do |spec|
     Dir["lib/**/*", "LICENSE.txt", "Rakefile", "README.md"]
   end
 
-  spec.add_dependency("ruby-lsp", ">= 0.21.0", "< 0.22.0")
+  spec.add_dependency("ruby-lsp", ">= 0.21.2", "< 0.22.0")
 end