filters/colorize: use /usr/bin/awk shebang

/bin is reserved for essential commands that may be used when in single
user mode.

Link: https://refspecs.linuxfoundation.org/FHS_3.0/fhs-3.0.html#binEssentialUserCommandBinaries
Signed-off-by: Robin Jarry <robin@jarry.cc>

filters/colorize

@@ -1,4 +1,4 @@
-#!/bin/awk -f
+#!/usr/bin/awk -f
 # Copyright (c) 2022 Robin Jarry
 
 BEGIN {