Merge branch 'master' into undocumented-feature-tags

.gitattributes

.github/workflows/php.yml

README.md

TESTING.md

bin/build-release.sh

config-templates/config.php

docs/simplesamlphp-changelog.md

lib/SimpleSAML/Auth/AuthenticationFactory.php

lib/SimpleSAML/Auth/ProcessingChain.php

lib/SimpleSAML/Auth/ProcessingFilter.php

lib/SimpleSAML/Auth/Simple.php

lib/SimpleSAML/Auth/Source.php

lib/SimpleSAML/Auth/State.php

lib/SimpleSAML/Command/RouterDebugCommand.php

lib/SimpleSAML/Configuration.php

lib/SimpleSAML/Database.php

lib/SimpleSAML/Error/AuthSource.php

lib/SimpleSAML/Error/BadRequest.php

lib/SimpleSAML/Error/ConfigurationError.php

lib/SimpleSAML/Error/CriticalConfigurationError.php