lint-history: do decode bytes

This fixes the "TypeError: a bytes-like object is required, not 'str'"
problem on Windows, letting t9391 pass.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

contrib/filter-repo-demos/lint-history

@@ -114,7 +114,7 @@ def lint_with_real_filenames(commit, metadata):
         f.write(contents_plus_newline[:-1])
 
       # Lint the file
-      subprocess.check_call(lint_args.command + [filename])
+      subprocess.check_call(lint_args.command + [filename.decode('utf-8')])
 
       # Get the new contents
       with open(filename, "rb") as f: