Change Ruby extension to ruby-lsp

This is the extension that is recommended in the VSCode documentation now. 

https://code.visualstudio.com/docs/languages/ruby

Author: rafaelfranca

src/ruby/devcontainer-feature.json

@@ -21,7 +21,7 @@
     "customizations": {
         "vscode": {
             "extensions": [
-                "rebornix.Ruby"
+                "Shopify.ruby-lsp"
             ]
         }
     },