Created attachment 14924 [details]
subunit/run.py: make iso8601 UTC usage python 2/3 compatible

In `subunit/run.py`:
 
    from iso8601.iso8601 import Utc
    
In `iso8601/iso8601.py`:

    if sys.version_info >= (3, 2, 0):
        UTC = datetime.timezone.utc
        ...
    else:
        class Utc(datetime.tzinfo):
            ...

        UTC = Utc()

The class `Utc` is only available for python < 3.2.0, which implies `subunit/run.py` will not work with python 3.2.0+.
Use `UTC` instance instead, which is python 2/3 compatible.

The attached patch has already been applied to master as 02c7b8c03d4970421a5170e44c57cbc3cda82827, backport needed.