reset colors after warning

If a warning is shown, and you happen to have no color setting in your (bash) prompt, the \033[37m setting, stays active. With the message hardly readable (light grey on my default light yellow background), that means the prompt is barely visible and you need to do `tput reset`.
Would probably be better if the background color was set as well in case you have dark on light theme by default in your terminal.

Signed-off-by: Anthon van der Neut <[email protected]>

contrib/migration/migrate-compose-file-v1-to-v2.py

@@ -155,7 +155,7 @@ def parse_opts(args):
 
 
 def main(args):
-    logging.basicConfig(format='\033[33m%(levelname)s:\033[37m %(message)s\n')
+    logging.basicConfig(format='\033[33m%(levelname)s:\033[37m %(message)s\033[0m\n')
 
     opts = parse_opts(args)