RHEL9 Support - Test cases to leverage unittest.mock when possible (#658)

test/test_plugin_sendgrid.py

@@ -22,7 +22,14 @@
 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 # THE SOFTWARE.
-import mock
+try:
+    # Python 3.x
+    from unittest import mock
+
+except ImportError:
+    # Python 2.7
+    import mock
+
 import pytest
 import requests
 from apprise import plugins