download_strategy: replace bazaar with breezy

Bazaar is no longer maintained, and Breezy seems to be a drop-in
replacement.

I've tested the commands used in the download strategy and they seem to
work.

We need this in order to properly deprecate the `bazaar` formula.

See Homebrew/homebrew-core#106848.

Library/Homebrew/download_strategy.rb

@@ -1280,7 +1280,7 @@ class BazaarDownloadStrategy < VCSDownloadStrategy
 
   def env
     {
-      "PATH"     => PATH.new(Formula["bazaar"].opt_bin, ENV.fetch("PATH")),
+      "PATH"     => PATH.new(Formula["breezy"].opt_bin, ENV.fetch("PATH")),
       "BZR_HOME" => HOMEBREW_TEMP,
     }
   end