Installer: Workaround pip 22.0 issues

scripts/KlipperScreen-install.sh

@@ -55,7 +55,13 @@ install_packages()
 create_virtualenv()
 {
     echo_text "Creating virtual environment"
-    [ ! -d ${KSENV} ] && virtualenv -p /usr/bin/python3 ${KSENV}
+    if [ ! -d ${KSENV} ]; then
+        GET_PIP="${HOME}/get-pip.py"
+        virtualenv --no-pip -p /usr/bin/python3 ${KSENV}
+        curl https://bootstrap.pypa.io/pip/3.6/get-pip.py -o ${GET_PIP}
+        ${KSENV}/bin/python ${GET_PIP}
+        rm ${GET_PIP}
+    fi
 
     source ${KSENV}/bin/activate
     while read requirements; do