Fix URLs to replace http with https

[giraffate]

Fix URLs to replace http with https because these URLs is redirected with status 301 or unintentionally visited with http.

Following are some examples.

curl -I http://www.evanmiller.org/ab-testing/sample-size.html
HTTP/1.1 200 OK
Server: nginx/1.14.0 (Ubuntu)
Date: Tue, 27 Aug 2019 13:28:07 GMT
Content-Type: text/html
Content-Length: 6113
Last-Modified: Wed, 16 Jan 2019 14:38:01 GMT
Connection: keep-alive
ETag: "5c3f41c9-17e1"
Accept-Ranges: bytes

curl -I http://github.com/splitrb/split-export
HTTP/1.1 301 Moved Permanently
Content-length: 0
Location: https://github.com/splitrb/split-export

[andrehjr]

✨