patch 8.2.4906: MS-Windows: cannot use transparent background

Problem:    MS-Windows: cannot use transparent background.
Solution:   Make transparent background work with 'termguicolors' and NONE
            background color. (Yasuhiro Matsumoto, closes #10310, closes #7162)
diff --git a/src/version.c b/src/version.c
index af4c0b2..d5963d4 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4906,
+/**/
     4905,
 /**/
     4904,