releases: conf: add link to 3.1.4, update to include 3.1.4

(From yocto-docs rev: 20b7be912040ae02fb2df652fb79b09dd5f281e8)

Signed-off-by: Michael Halstead <mhalstead@linuxfoundation.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/sphinx-static/switchers.js

@@ -4,7 +4,7 @@
   var all_versions = {
     'dev': 'dev (3.3)',
     '3.2': '3.2',
-    '3.1.3': '3.1.3',
+    '3.1.4': '3.1.4',
     '3.0.4': '3.0.4',
     '2.7.4': '2.7.4',
   };