ditch travis in favor of gha workflow

[falkenhawk]

It's time to ditch travis.
Even though it kinda works at the moment after they topped up the oss credits, but it again started failing on php 5.3.
But, thanks to @glensc, tests are ported to run on Github Actions. 🎉

Current status - travis: (php 8.0)

OK, but incomplete or skipped tests!

Tests: 15522, Assertions: 61406, Incomplete: 22, Skipped: 607.

GHA: (php 8.0)

OK, but incomplete or skipped tests!
Tests: 15572, Assertions: 61707, Incomplete: 21, Skipped: 585.

There are even less tests skipped on GHA compared to travis. 🎉

Note: postgres and sqlite tests are not performed at the moment, but they may be added at a later date. Even without them, the total number of run tests are higher than on travis.

[falkenhawk]

haha, I tried my luck with re-enabling tests which have been always skipped because they "randomly fail on Travis CI"

It looks like failures are not random on GHA, as they happened on every run in https://github.com/zf1s/zf1/runs/3765273246 😅

There must be something off going on inside Zend_Cache... but I will make the tests skipped again for now and hopefully tackle that in a separate PR (somewhen...)

[falkenhawk]

It may be not that bad after all, as failures seems to be deterministic and there is only one cache backend failing ("Memcached"):

1) Zend_Cache_MemcachedBackendTest::testCleanModeAll
Failed asserting that false is true.

/home/runner/work/zf1/zf1/tests/Zend/Cache/CommonBackendTest.php:234

[falkenhawk]

postgres enabled in #114