Add php 7 and 8

[b1rdex]

Had to drop php 5.3

[b1rdex]

Here is build log: https://travis-ci.com/b1rdex/phpiredis/builds/105300525

[b1rdex]

Here is last build log with CFLAGS set: https://travis-ci.com/b1rdex/phpiredis/builds/105302618

[b1rdex]

The build is green: https://travis-ci.com/github/b1rdex/phpiredis/builds/177896588

[nrk]

Hi @b1rdex, just wondering: would it be possible to keep tests running on PHP 5.3, 5.4 and 5.5 on Travis CI just like we did with Predis? We could also add PHP 8.0 while we are at this, planning to merge #66 in a few days.

[b1rdex]

@nrk I've added 5.3, 5.4 and 5.5 back and added 8.0. The build passed (https://travis-ci.com/github/b1rdex/phpiredis/builds/189732401) except for 8.0. Then I decided to update the branch and rebase it over v1.1. And now it's broken: https://travis-ci.com/github/b1rdex/phpiredis/builds/189734122. I don't get why and can't fix it. What should I do next? 😄

Also, could you please fix Travis integration? Would be easier to see the build status here on GitHub.

[b1rdex]

Actually, v1.1 branch errors too: https://travis-ci.com/github/b1rdex/phpiredis/builds/189735956