fix redirect file syntax (#201)

Author: Chris Cho

config/redirects

@@ -5,4 +5,4 @@ define: versions v4.3 v4.4 master
 raw: ${prefix}/ -> ${base}/current/
 raw: ${prefix}/master -> ${base}/upcoming/
 
-[*-master]: ${prefix}/${version}/fundamentals/versioned-api/ -> ${prefix}/${version}/fundamentals/stable-api/
+[*-master]: ${prefix}/${version}/fundamentals/versioned-api/ -> ${base}/${version}/fundamentals/stable-api/