homebrew: Include version information in resources

tools/apps/update_homebrew/bin/update_homebrew.dart

Index: tools/apps/update_homebrew/bin/update_homebrew.dart
diff --git a/tools/apps/update_homebrew/bin/update_homebrew.dart b/tools/apps/update_homebrew/bin/update_homebrew.dart
index 800fae1faf849741c20f75d4f0aa2af31207cbd8..a1e458619ab40ccf20bfe64c01024dcedcb53d6f 100644
--- a/tools/apps/update_homebrew/bin/update_homebrew.dart
+++ b/tools/apps/update_homebrew/bin/update_homebrew.dart
@@ -205,22 +205,26 @@ class Dart < Formula
     end
 
     resource 'content_shell' do
+      version '$devVersion'
       url '$urlBase/dev/release/${revisions['dev']}/$contentShellFile'
       sha256 '${hashes['dev'][contentShellFile]}'
     end
 
     resource 'dartium' do
+      version '$devVersion'
       url '$urlBase/dev/release/${revisions['dev']}/$dartiumFile'
       sha256 '${hashes['dev'][dartiumFile]}'
     end
   end
 
   resource 'content_shell' do
+    version '$stableVersion'
     url '$urlBase/stable/release/${revisions['stable']}/$contentShellFile'
     sha256 '${hashes['stable'][contentShellFile]}'
   end
 
   resource 'dartium' do
+    version '$stableVersion'
     url '$urlBase/stable/release/${revisions['stable']}/$dartiumFile'
     sha256 '${hashes['stable'][dartiumFile]}'
   end