Fix Travis CI badge URL and landing page URL (#969)
Fix Travis CI badge URL and landing page URL (#969)

The current URL (https://www.travis-ci.com/cayleygraph/cayley) returns a 404, so update
to the correct URL https://app.travis-ci.com/github/cayleygraph/cayley .

Additionally, the image URL redirects to the api.travis-ci.com hostname, so fix that as well.

Since this change isn't modifying any code and shouldn't affect the build, we can [skip ci].
cayleygraph/cayley,cayleygraph/cayley