Explain venv if needed

Author: ofaurax

README.md

@@ -32,6 +32,13 @@ Reference the Dockerfile for other dependency requirements.
 pip3 install git+https://github.com/packethost/packet-hardware.git@master
 ```
 
+if it fails, you may need to use a venv:
+```
+python3 -m venv phenv
+. phenv/bin/activate
+pip install git+https://github.com/packethost/packet-hardware.git@master
+```
+
 Install required tools:
 - Alpine: `apk add dmidecode ipmitool smartmontools hdparm ethtool`