Use python3 pip module instead of pip binary

Focal only provides a pip3 binary, no pip3.8. Instead of working around
that with a symlink, use the module instead.

Add version information output for this variant.

Change-Id: I7af194ecc40e4d43c10ce067a661bb6ab4ca37d4
diff --git a/inc/python b/inc/python
index dd77296..08f9959 100644
--- a/inc/python
+++ b/inc/python
@@ -174,7 +174,7 @@
         if python3_enabled; then
             echo "Using python $PYTHON3_VERSION to install $package_dir because python3_enabled=True"
             sudo_pip="$sudo_pip LC_ALL=en_US.UTF-8"
-            cmd_pip=$(get_pip_command $PYTHON3_VERSION)
+            cmd_pip="python$PYTHON3_VERSION -m pip"
         else
             echo "Using python $PYTHON2_VERSION to install $package_dir because python3_enabled=False"
             cmd_pip=$(get_pip_command $PYTHON2_VERSION)
@@ -217,7 +217,7 @@
         local sudo_pip="sudo -H"
         if python3_enabled; then
             sudo_pip="$sudo_pip LC_ALL=en_US.UTF-8"
-            cmd_pip=$(get_pip_command $PYTHON3_VERSION)
+            cmd_pip="python$PYTHON3_VERSION -m pip"
         else
             cmd_pip=$(get_pip_command $PYTHON2_VERSION)
         fi