php 8.1 return type "fix" for now

namespace fixes

Merge branch 'maximebf:master' into master

Merge pull request #3 from EurekaRanch/upstream_updates

Revert "remove workflow"

switch to non-deprecated classes

Symfony 5 support added (php-debugbar#431)

Update .travis.yml

Fetch support (php-debugbar#422)

Fetch support (php-debugbar#422)

Update JavascriptRenderer.php