Build venvs with py3

Author: owais

Makefile

@@ -22,7 +22,7 @@ build: clean
 
 install:
 @echo "Installing build dependencies"
-@[ ! -d $(ENV)/ ] && virtualenv $(ENV)/ || :
+@[ ! -d $(ENV)/ ] && python3 -m venv $(ENV)/ || :
 @$(ENV)/bin/pip install $(requirements)
 
 generate-rst: