Fix achievements test

Author: algomaster99

experimentation/tools/tests/test_achievements.py

@@ -30,7 +30,7 @@ def test_correctly_renders_merged_pr(tmp_path):
 This document presents an overview of the pull requests performed with Sorald.
 
 ## [redhat-developer/rsp-server#619](https://github.com/redhat-developer/rsp-server/pull/619)
-This PR was opened at 2020-11-25 12:01:06 and merged at 2020-11-30 20:45:38.
+This PR was opened at 2020-11-25 12:01:06+00:00 and merged at 2020-11-30 20:45:38+00:00.
 The patch was generated fully automatically with Sorald.
 
 It provided the following repairs:
@@ -70,7 +70,7 @@ def test_correctly_renders_pr_without_repair_data(tmp_path):
 This document presents an overview of the pull requests performed with Sorald.
 
 ## [redhat-developer/rsp-server#619](https://github.com/redhat-developer/rsp-server/pull/619)
-This PR was opened at 2020-11-25 12:01:06 and merged at 2020-11-30 20:45:38.
+This PR was opened at 2020-11-25 12:01:06+00:00 and merged at 2020-11-30 20:45:38+00:00.
 The patch was generated fully automatically with Sorald.
 
 Detailed repair information is missing for this PR.""".strip()