fix: make sure that the build epoch is *always* updated whenever the distribution packages are being built (#1118)

Author: jenstroeger

Makefile

@@ -191,6 +191,9 @@ dist/$(PACKAGE_NAME)-$(PACKAGE_VERSION)-docs-html.zip: docs-html
 	python -m zipfile -c dist/$(PACKAGE_NAME)-$(PACKAGE_VERSION)-docs-html.zip docs/_build/html/
 dist/$(PACKAGE_NAME)-$(PACKAGE_VERSION)-docs-md.zip: docs-md
 	python -m zipfile -c dist/$(PACKAGE_NAME)-$(PACKAGE_VERSION)-docs-md.zip docs/_build/markdown/
+
+# Keep this goal phony to ensure the epoch is always updated.
+.PHONY: dist/$(PACKAGE_NAME)-$(PACKAGE_VERSION)-build-epoch.txt
 dist/$(PACKAGE_NAME)-$(PACKAGE_VERSION)-build-epoch.txt:
 	echo $(SOURCE_DATE_EPOCH) > dist/$(PACKAGE_NAME)-$(PACKAGE_VERSION)-build-epoch.txt