GA: build.yml - PHPStan - updated PHP versions

Fixed PHPStan errors

GitRepository: method run() is public now (czproject#100)

Git: isRemoteUrlReadable() - returns TRUE for empty repositories

Closes czproject#92

Runners: added OldGitRunner

czproject#82
czproject#86

GitRepository: pull(), push() & fetch() - accepts string[] in $remote

czproject#77 (comment)

GitRepository: checkout - removed '--end-of-options' (closes czprojec…

…t#77)

Uses --end-of-options after command options (for security reasons)

GitRepository: fixed parameters in `git log` commands (closes czproje…

…ct#70)

CliRunner: coding style