Tooling needs an update, automated testing fails.

[nreynis]

Tooling is out of date and cause tests to fail:

• travis for HHVM fails because composer dropped support:
  composer/composer#8127
  You should probably drop it too.
• travis for nightly fails because there´s currently no stable release of phpUnit supporting PHP8
  IMHO you should temporarly disable nightly and update to current phpUnit release
• appveyor fails because php version has been bumped from 7.2 to 7.3

If you want I can take some time to provide a PR.

[florianeckerstorfer]

Yes, fixed in #40