remove github workflow from gitignore and add .pdm-python

Not sure why a random no longer present workflow was added to the gitignore in the first place, but it has no reason to be there now.

Author: khakers

.gitignore

@@ -138,4 +138,5 @@ config.json
 temp/
 test.py
 stack.yml
-.github/workflows/build_docker.yml
+
+.pdm-python