patch 7.4.1745

Problem:    README file is not clear about where to get Vim.
Solution:   Add links to github, releases and the Windows installer.
            (Suggested by Christian Brabandt)

src/version.c

@@ -748,6 +748,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1745,
 /**/
     1744,
 /**/