Fix deprecation warnings for botocore use of datetime.now().

.github/workflows/unit-tests.yaml

@@ -24,4 +24,4 @@ jobs:
           python -m pip install -r requirements-tests.txt --no-deps
       - name: Run tests
         run: |
-          python -m unittest discover .
+          python -W error -m unittest --verbose

tests/test_examples.py

@@ -11,6 +11,7 @@
 import unittest
 import unittest.mock
 import urllib.parse
+import warnings
 
 try:
     from dateutil.tz import tzlocal
@@ -35,6 +36,16 @@
 from examples.xkcd import ComicVersion, XKCDResource
 
 
+def setUpModule() -> None:
+    """Code to run before any single test in the module is run."""
+    warnings.filterwarnings("ignore", category=DeprecationWarning, module="botocore.auth")
+
+
+def tearDownModule() -> None:
+    """Code to run after every single test in the module has been run."""
+    warnings.filterwarnings("default", category=DeprecationWarning, module="botocore.auth")
+
+
 class MockedTextResponse:
     """
     Represents a mocked requests.Response object containing a body.