FIX: Use timezone.utc instead of datetime.UTC

src/icartt/dataset.py

@@ -983,8 +983,8 @@ class Dataset:
         self.missionName = "MUSTEREX"
 
         # .utcnow() should not be used in general, but it is ok if you just need the timetuple.
-        self.dateOfCollection = datetime.datetime.now(datetime.UTC).timetuple()[:3]
-        self.dateOfRevision = datetime.datetime.now(datetime.UTC).timetuple()[:3]
+        self.dateOfCollection = datetime.datetime.now(datetime.timezone.utc).timetuple()[:3]
+        self.dateOfRevision = datetime.datetime.now(datetime.timezone.utc).timetuple()[:3]
         self.dataIntervalCode = [0.0]
 
         self.independentVariable = None