patch 8.1.0639: text properties test fails on MS-Windows

Problem:    text properties test fails on MS-Windows
Solution:   Set fileformat to "unix".
diff --git a/src/version.c b/src/version.c
index 5cffe09..30f2899 100644
--- a/src/version.c
+++ b/src/version.c
@@ -800,6 +800,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    639,
+/**/
     638,
 /**/
     637,