Resolved DeprecationWarning for currentThread()

In Python 3.10 onwards we see a DeprecationWarning:
currentThread() is deprecated, use current_thread() instead.
Same goes for getName(), replaced by name attribute.

Test: tox (python 3.6 - 3.10)

Signed-off-by: Daniel Kutik <daniel.kutik@lavawerk.com>
Change-Id: I80ec819752a5276cff3b2dadba0ec10cc92d09a4
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/353018
Reviewed-by: Mike Frysinger <vapier@google.com>

git_trace2_event_log.py

@@ -110,7 +110,7 @@ class EventLog(object):
     return {
         'event': event_name,
         'sid': self._full_sid,
-        'thread': threading.currentThread().getName(),
+        'thread': threading.current_thread().name,
         'time': datetime.datetime.utcnow().isoformat() + 'Z',
     }