[vte] parser: Properly refer to python3

[Rico Tzschichholz <ricotz src gnome org>]

commit d48a80b8ec417541717f74ae622a78dc1ef068f4
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Mon Oct 19 20:00:22 2020 +0200

    parser: Properly refer to python3
    
    https://gitlab.gnome.org/GNOME/vte/-/issues/292

 src/parser-seq.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/parser-seq.py b/src/parser-seq.py
index 90a68246..7ee79c8d 100755
--- a/src/parser-seq.py
+++ b/src/parser-seq.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 #
 # Copyright © 2015 David Herrmann <dh herrmann gmail com>
 # Copyright © 2018, 2019, 2020 Christian Persch