Use versioned get-pip.py URL for Ubuntu Bionic

Pip 22.0 doesn't support Python versions prior to 3.7, so the
unversioned get-pip.py script refuses to run under Ubuntu Bionic's
default python3 interpreter. Add a 3.6-specific URL instead to work
around this.

Change-Id: Icab5f4dd45d8f290a2f52db083cdc564e5a08776

playbooks/roles/pip3/tasks/bionic.yaml

@@ -0,0 +1,6 @@
+# Latest pip (and get-pip.py) does not support the Python 3.6 on Ubuntu Bionic
+- name: Download get-pip.py
+  command: wget https://bootstrap.pypa.io/pip/3.6/get-pip.py
+  args:
+    chdir: /var/lib
+    creates: /var/lib/get-pip.py