[stable-2.8] Ignore warnings in ansible-test environment check.

(cherry picked from commit 3db1ac4f56)

Co-authored-by: Matt Clay <matt@mystile.com>

changelogs/fragments/ansible-test-ignore-pip-warnings.yml

@@ -0,0 +1,2 @@
+bugfixes:
+    - ansible-test now ignores warnings when comparing pip versions before and after integration tests run

test/runner/versions.py

@@ -3,6 +3,9 @@
 
 import os
 import sys
+import warnings
+
+warnings.simplefilter('ignore')  # avoid python version deprecation warnings when using newer pip dependencies
 
 try:
     import pip