logging_tools: fix invalid escape sequence

sipyco/logging_tools.py

@@ -54,7 +54,7 @@ def log_with_name(name, *args, **kwargs):
 
 def parse_log_message(msg):
     lr = "|".join(_name_to_level.keys())
-    m = re.fullmatch('('+lr+')(<\d+>)?:([^:]*):(.*)', msg)
+    m = re.fullmatch('('+lr+')(<\\d+>)?:([^:]*):(.*)', msg)
     if m is None:
         return 0, logging.INFO, "print", msg
     level = _name_to_level[m.group(1)]