Fix first and last paginator links.
The "first" was incorrectly pointing to "../1" when it should've pointed to "..". This is because despite there being "/packages/2", "/packages/3", etc, the first page is just "/packages".
For the exact same reason, the "last" button was broken, but only on page one. This is because the last page is defined by "../total_pages". When you are on "/packages/2" this works fine. But when you are on "/packages" then it breaks.
See https://github.com/sverrirs/jekyll-paginate-v2/issues/28