patch 8.1.0105: all tab stops are the same

Problem:    All tab stops are the same.
Solution:   Add the variable tabstop feature. (Christian Brabandt,
            closes #2711)

src/version.c

@@ -676,6 +676,11 @@ static char *(features[]) =
 	"+user_commands",
 #else
 	"-user_commands",
+#endif
+#ifdef FEAT_VARTABS
+	"+vartabs",
+#else
+	"-vartabs",
 #endif
 	"+vertsplit",
 #ifdef FEAT_VIRTUALEDIT
@@ -778,6 +783,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    105,
 /**/
     104,
 /**/