Allow flask 2 for webservice (#816)

* Allow flask 2 for webservice.

The breaking changes do not appear to affect it.

* Add shebang to webservice script.

misc/webservice.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 # webservice.py wrapper for OCRmyPDF
 # Copyright (C) 2019 James R. Barlow: github.com/jbarlow83
 #
@@ -36,7 +37,6 @@ from flask import (
     redirect,
     request,
     send_from_directory,
-    url_for,
 )
 from werkzeug.utils import secure_filename
 

setup.cfg

@@ -86,7 +86,7 @@ extended_test =
 watcher =
     watchdog >= 1.0.2, < 3
 webservice =
-    Flask >= 1, < 2
+    Flask >= 1, < 3
 
 [options.entry_points]
 console_scripts =