Create sksl_enums.inc with UNIX line endings (even on Windows)

Change-Id: I6e17a8498647c4bd09281f880a94cbfdcd5930ea
Reviewed-on: https://skia-review.googlesource.com/106020
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>

gn/create_sksl_enums.py

@@ -10,7 +10,7 @@ import subprocess
 import sys
 
 src = open(sys.argv[1], 'r')
-dst = open(sys.argv[2], 'w')
+dst = open(sys.argv[2], 'wb')
 dst.write('R"(')
 for line in src.readlines():
     if not line.startswith("#"):