Fix mkvenv - freeze with outdated not supported

mkvenv

 if [ ! -e venv ];then
-    virtualenv venv
+    python3 -m venv venv
     if venv/bin/pip -V | grep `pwd -P`; then
         venv/bin/pip install --upgrade pip
         find . -name requirements.txt | xargs -L 1 venv/bin/pip install -r
-        venv/bin/pip list --outdated --format=freeze | grep -v '^\-e' | cut -d = -f 1 | xargs -n1 venv/bin/pip install -U
+        venv/bin/pip list --outdated --format=json | jq -r '.[] | .name'|xargs -n1 venv/bin/pip install -U
     else
         echo Not running in the venv!
     fi