Require certifi package and python3 in my_activity

my_activity.py talks to third party (e.g. review.coreboot.org). Without
certifi package, making https connection may result in
CERTIFICATE_VERIFY_FAILED.

Adding certifi package to .vpython (py2) doesn't work, so this change
drops py2 support for my_activity.py.

R=gavinmak@google.com

Fixed: 1255921
Change-Id: I515b14c81d37a52d482d08085d8029c791911ae8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3206906
Auto-Submit: Josip Sokcevic <sokcevic@google.com>
Reviewed-by: Gavin Mak <gavinmak@google.com>
Commit-Queue: Josip Sokcevic <sokcevic@google.com>
diff --git a/my_activity.py b/my_activity.py
index 3fdd7cf..874f9f3 100755
--- a/my_activity.py
+++ b/my_activity.py
@@ -57,13 +57,10 @@
 import gclient_utils
 import gerrit_util
 
-
 if sys.version_info.major == 2:
-  logging.warning(
-      'Python 2 is deprecated. Run my_activity.py using vpython3.')
-  import urllib as urllib_parse
-else:
-  import urllib.parse as urllib_parse
+  logging.critical(
+      'Python 2 is not supported. Run my_activity.py using vpython3.')
+
 
 try:
   import dateutil  # pylint: disable=import-error
@@ -348,7 +345,7 @@
     http = self.monorail_get_auth_http()
     url = ('https://monorail-prod.appspot.com/_ah/api/monorail/v1/projects'
            '/%s/issues') % project
-    query_data = urllib_parse.urlencode(query)
+    query_data = urllib.parse.urlencode(query)
     url = url + '?' + query_data
     _, body = http.request(url)
     self.show_progress()