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.

src/version.c

@@ -769,6 +769,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    748,
 /**/
     747,
 /**/