Formula-Cookbook: recommend gdm for go resources

Closes Homebrew/homebrew#46889.

Signed-off-by: Dominyk Tiller <dominyktiller@gmail.com>

share/doc/homebrew/Formula-Cookbook.md

@@ -225,7 +225,7 @@ end
 
 [jrnl](https://github.com/Homebrew/homebrew/blob/master/Library/Formula/jrnl.rb) is an example of a formula that does this well. The end result means the user doesn't have use `pip` or Python and can just run `jrnl`.
 
-[homebrew-pypi-poet](https://github.com/tdsmith/homebrew-pypi-poet) can help you generate resource stanzas for the dependencies of your Python application and [homebrew-go-resources](https://github.com/samertm/homebrew-go-resources) can help you generate go\_resource stanzas for the dependencies of your go application.
+[homebrew-pypi-poet](https://github.com/tdsmith/homebrew-pypi-poet) can help you generate resource stanzas for the dependencies of your Python application and [gdm](https://github.com/sparrc/gdm#homebrew) can help you generate go\_resource stanzas for the dependencies of your go application.
 
 ## Install the formula