Update requirements.txt

Change-Id: I31118b9b7df2edafd81647ec8d88f46b5a701355
diff --git a/Makefile b/Makefile
index 2aca763..af0e2bf 100644
--- a/Makefile
+++ b/Makefile
@@ -55,6 +55,9 @@
 	python3 -m venv $(VENV)
 	$(PIP) install -r requirements.txt
 
+freeze:
+	pip3 freeze | grep -v "pkg-resources" > requirements.txt
+
 docker-build: $(VENV)
 	docker build $(DOCKER_BUILD_ARGS) \
 		-t $(DOCKER_IMAGENAME) \