Use https where possible

docs/content/index/index.yml

@@ -27,8 +27,8 @@ tail: |
   Go read the [tutorial](tutorial/) for more, or the [manual](manual/)
   for *way* more.
 
-  Ask questions on [stackoverflow](http://stackoverflow.com/) using the [jq
-  tag](http://stackoverflow.com/questions/tagged/jq), or on the
+  Ask questions on [stackoverflow](https://stackoverflow.com/) using the [jq
+  tag](https://stackoverflow.com/questions/tagged/jq), or on the
   [#jq](http://irc.lc/freenode/%23jq/) channel on
   [Freenode](https://webchat.freenode.net/).