upgrade vim-flavor 4.0 for Ruby 3.0 compatibility

Author: sunaku

Gemfile

@@ -1,2 +1,2 @@
 source 'https://rubygems.org'
-gem 'vim-flavor', '~> 3.0'
+gem 'vim-flavor', '~> 4.0'

Gemfile.lock

@@ -1,23 +1,21 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    equatable (0.6.1)
-    parslet (1.8.2)
-    pastel (0.7.3)
-      equatable (~> 0.6)
+    parslet (2.0.0)
+    pastel (0.8.0)
       tty-color (~> 0.5)
-    thor (0.20.3)
-    tty-color (0.5.0)
-    vim-flavor (3.0.0)
-      parslet (~> 1.8)
+    thor (1.2.1)
+    tty-color (0.6.0)
+    vim-flavor (4.0.2)
+      parslet (>= 1.8, < 3.0)
       pastel (~> 0.7)
-      thor (~> 0.20)
+      thor (>= 0.20, < 2.0)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
-  vim-flavor (~> 3.0)
+  vim-flavor (~> 4.0)
 
 BUNDLED WITH
-   1.17.2
+   2.2.17