Chore: update makefile

Makefile

@@ -3,6 +3,7 @@
 .ONESHELL: ;             # recipes execute in same shell
 .NOTPARALLEL: ;          # wait for this target to finish
 .EXPORT_ALL_VARIABLES: ; # send all vars to shell
+.DEFAULT_GOAL := help
 
 UID := $(shell id -u)
 GID := $(shell id -g)
@@ -15,4 +16,16 @@ pull:
 chown:
 	sudo chown -R $(UID):$(GID) .
 deploy:
-	docker run --rm -it -v ~/.ssh:/root/.ssh -v ${PWD}:/docs squidfunk/mkdocs-material gh-deploy
+	docker run --rm -it -v ~/.ssh:/root/.ssh -v ${PWD}:/docs squidfunk/mkdocs-material gh-deploy
+clean:
+	rm -rf ./env ./site
+
+help:
+	@echo "=== Project build help ==="
+	@echo ""
+	@echo "These targets are available:"
+	@echo "- watch"
+	@echo "- pull"
+	@echo "- chown"
+	@echo "- deploy"
+	@echo "- clean"