Run tests on PHP 8.3 and update test suite

Remove legacy sigchild compatibility layer

Update test suite and report failed assertions

Hello `0.7.x` development branch

Test on PHP 8.2

With PHP 8.2 coming out later this year, we should be reading for it's release to ensure all out...

Skip failing tests on bugged versions (PHP 8.1.8)

Skip failing tests on bugged versions (PHP 8.1.7 and PHP 8.0.20 only)

chore(docs): remove leading dollar sign

Improve error reporting when custom error handler is used

Fix legacy HHVM build by downgrading Composer

Add badge to show number of project installations

Simplify usage by supporting new default loop

Support PHP 8 and add non-blocking I/O support on Windows with PHP 8

Use GitHub actions for continuous integration (CI)

Bye bye Travis CI, you've served us well.

Run tests on PHPUnit 9 and update PHPUnit configuration schema for PHPUnit 9.3

Run tests on PHP 7.4

Update docblock for Process::$pipes

Found this when running Psalm in a project of mine that is using reactphp/child-process.
```
Pos...

Add full core team to the license

Added the full core team in order of joining the team

Add .gitattributes to exclude dev files from exports

Improve error reporting when spawning child process fails

Suppress PHP warnings on error and report any error message as part of
exception messages as exp...

Run tests on Windows via Travis CI

Improve documentation for exit event and minor docblock updates

Improve performance by prefixing all global functions calls with \ to skip the look up and resol...

Support spawning child process on Windows without process I/O pipes

Test against PHP7.2 and PHP 7.3, improve HHVM compatibility and add forward compatibility with P...

Additionally, use legacy PHPUnit 5 for legacy HHVM on Travis CI as per
https://github.com/clue/p...

Support passing custom pipes and file descriptors to child process

Expose all standard I/O pipes in an array

Improve sigchild compatibility and support explicit configuration

Remove unused options passed to proc_open() (Windows only)

Fix typo

Detect exit immediately if last process pipe is closed

Fix forward compatibility with upcoming EventLoop releases

Fix test suite race condition by catching namespaced Exception variant

Forward compatibility with PHPUnit 6

Simplify test bootstrapping logic via Composer

Update Stream dependency to work around SEGFAULT in legacy PHP < 5.4.28 and PHP < 5.5.12

Remove now unneeded buffer workaround for legacy PHP < 5.4