upgrade Python to v 3.8 (operator-framework#4413)

* upgrade Python to v 3.8
* add change notes
* add python to installation guide

Signed-off-by: reinvantveer <reinvantveer@gmail.com>
Signed-off-by: Rein van 't Veer <reinvantveer@gmail.com>
Signed-off-by: reinvantveer <rein.van.t.veer@geodan.nl>

changelog/fragments/upgrade-python-on-ansible-operator.yaml

@@ -0,0 +1,11 @@
+entries:
+  - description: >
+      For Ansible-based operators, the Python version has been updated
+      to a newer version, from 3.6 to 3.8 to take advantage of performance
+      improvements, language additions, security updates and generally
+      better availability for local development.
+
+    kind: change
+
+    # Is this a breaking change?
+    breaking: false