patch 8.0.0748: running Vim in terminal window doesn't use the right colors

Problem:    When running Vim in a terminal window it does not detect the right
            number of colors available.
Solution:   Detect the version string that libvterm returns.  Pass the number
            of colors in $COLORS.
diff --git a/src/version.c b/src/version.c
index 79e503f..0564b8f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -770,6 +770,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    748,
+/**/
     747,
 /**/
     746,