build: slightly more modern release processes

Author: nedbat

Makefile

@@ -30,4 +30,8 @@ kit:					## Make the source distribution.
 	python -m twine check dist/*
 
 kit_upload:				## Upload the built distributions to PyPI.
-	twine upload --verbose dist/*
+	python -m twine upload --verbose dist/*
+
+tag: ## Make a git tag with the version number
+	git tag -a -m "Version v$$(python setup.py --version)" v$$(python setup.py --version)
+	git push --all

howto.txt

@@ -11,5 +11,5 @@
 - Kits:
     $ make clean kit
     $ make kit_upload
-- tag git
+    $ make tag
 - make a new gh release: https://github.com/nedbat/django_coverage_plugin/releases/new