refactor: add future annotations imports (#398)

##### SUMMARY

This adds future annotations imports to benefit from the modern python
typing system.

.azure-pipelines/scripts/combine-coverage.py

@@ -7,6 +7,7 @@ Keep in mind that Azure Pipelines does not enforce unique job display names (onl
 It is up to pipeline authors to avoid name collisions when deviating from the recommended format.
 """
 
+from __future__ import annotations
 
 import os
 import re

.azure-pipelines/scripts/time-command.py

@@ -1,6 +1,7 @@
 #!/usr/bin/env python
 """Prepends a relative timestamp to each input line from stdin and writes it to stdout."""
 
+from __future__ import annotations
 
 import sys
 import time