Move to Python 3.8

Change-Id: I4fa658405174573f285f04bad212e0b67b40d1b9

releasenotes/notes/move-to-python-3.8-86095fce6076fb37.yaml

@@ -0,0 +1,6 @@
+---
+upgrade:
+  - |
+    Update Python base version from 3.6 to 3.8. As per Openstack Python
+    runtime versions policy Python 3.8 is the minimum Python version
+    in the Zed release cycle.

setup.cfg

@@ -6,7 +6,7 @@ description_file =
 author = OpenStack
 author_email = openstack-discuss@lists.openstack.org
 home_page = https://docs.openstack.org/octavia-dashboard/latest/
-python_requires = >=3.6
+python_requires = >=3.8
 classifier =
     Environment :: OpenStack
     Intended Audience :: Information Technology
@@ -17,10 +17,9 @@ classifier =
     Programming Language :: Python :: Implementation :: CPython
     Programming Language :: Python :: 3 :: Only
     Programming Language :: Python :: 3
-    Programming Language :: Python :: 3.6
-    Programming Language :: Python :: 3.7
     Programming Language :: Python :: 3.8
     Programming Language :: Python :: 3.9
+    Programming Language :: Python :: 3.10
 
 [files]
 packages =