build: fix the tagging

Author: nedbat

Makefile

@@ -36,8 +36,10 @@ pypi:					## Upload the built distributions to PyPI.
 test_pypi:				## Upload the distributions to test PyPI.
 	python -m twine upload --verbose --repository testpypi --password $$TWINE_TEST_PASSWORD dist/*
 
+VERSION := $(shell python -c "import django_coverage_plugin as me; print(me.__version__)")
+
 tag:					## Make a git tag with the version number.
-	git tag -s -m "Version v$$(python -c 'import django_coverage_plugin; print(django_coverage_plugin.__version__)')" v$$(python -c 'import django_coverage_plugin; print(django_coverage_plugin.__version__)')
+	git tag -s -m "Version v$(VERSION)" v$(VERSION)
 	git push --all
 
 ghrelease:				## Make a GitHub release for the latest version.

requirements.txt

@@ -3,3 +3,7 @@ tox >= 1.8
 build
 scriv
 twine
+
+# We need django and coverage to be able to import ourselves to make a tag...
+django
+coverage