Update instructions for pushing changes to PyDev.Debugger (#1715)

* Update instructions

* Update attach to process.yml

* Update binaries

Author: rchiodo

.github/workflows/attach_to_process.yml

@@ -1,4 +1,5 @@
 # Used to build binaries under src/debugpy/_vendored/pydevd/pydevd_attach_to_process
+# requires changes to this file or something under that path to run.
 name: attach_to_process
 
 on:

CONTRIBUTING.md

@@ -126,8 +126,10 @@ If you've made changes to pydevd (at src/debugpy/_vendored/pydevd), you'll want
 
 To do this, you would:
 
+- Create a fork of https://github.com/fabioz/PyDev.Debugger
+- Switch back to your debugpy clone
 - python subrepo.py branch -m "pydevd branch you want to create"
-- git push -f https://github.com/fabioz/PyDev.Debugger subrepo/src/debugpy/_vendored/pydevd:$(pydevd branch you want to create)
+- git push -f https://github.com/"your fork"/PyDev.Debugger subrepo/src/debugpy/_vendored/pydevd:$(pydevd branch you want to create)
 - Create a PR from that branch
 - Get Fabio's buyoff on the changes