php8.4 (#24)

* php8.4

* add php 8.4 to test matrix

improved local test methods (#18)

update readme - packagist link

Move phpunit files (#15)

* move phpunit files to clean up the root directory
* disable html coverage to save space, but gather the output in the artifact

Single artifact coverage (#14)

* Try to have one artifact with coverages from all php versions

* test each week + use datetime in filename for coverage

* test php 8.2

* remove test for php 8.2-nightly again (phpunit not ready)

update badges