ensure python 3.10 compatibility for datetime.UTC

See #169

Author: Konfekt

py/image.py

@@ -2,6 +2,12 @@
 import datetime
 import os
 
+try:
+    utc = datetime.UTC  # Python 3.11+
+except AttributeError:
+    utc = datetime.timezone.utc  # Older versions
+
+timestamp = datetime.datetime.now(utc).strftime("%Y%m%dT%H%M%SZ")
 image_py_imported = True
 
 def make_image_path(ui):