Unify naming of Makefile targets

Makefile

@@ -177,12 +177,12 @@ help:
 	@echo "  mypy                       Perform mypy checks.."
 	@echo "  bandit                     Perform bandit checks."
 	@echo "  clean                      Clean up build and test artifacts."
-	@echo "  create_env                 Create test environment."
-	@echo "  start_env                  Start test environment runtime."
-	@echo "  stop_env                   Stop test environment runtime."
-	@echo "  clean_env                  Clean up test environment."
+	@echo "  create-env                 Create test environment."
+	@echo "  start-env                  Start test environment runtime."
+	@echo "  stop-env                   Stop test environment runtime."
+	@echo "  clean-env                  Clean up test environment."
 	@echo "  debuild                    Build Debian package."
-	@echo "  clean_debuild              Clean up build and test artifacts including ones produced by"
+	@echo "  clean-debuild              Clean up build and test artifacts including ones produced by"
 	@echo "                             debuild target outside the project worksapce."
 	@echo "  format                     Re-format source code to conform style settings enforced by"
 	@echo "                             isort and black tools."