Update TastyIgniter Installer

[sampoyigi]

This PR updates the TastyIgniter installer to use data defined under the extra property when determining the install path.

[sampoyigi]

Can't get the phpstan check to pass, what am I missing?

[sampoyigi]

@niksamokhvalov could you please have a look?

[niksamokhvalov]

Error: ] Found 2 errors                                                         
[101](https://github.com/composer/installers/runs/5038318637?check_suite_focus=true#step:7:101)

[102](https://github.com/composer/installers/runs/5038318637?check_suite_focus=true#step:7:102)
Error: Parameter #3 $subject of function preg_replace expects array|string, string|null given.
[103](https://github.com/composer/installers/runs/5038318637?check_suite_focus=true#step:7:103)
Error: Method Composer\Installers\TastyIgniterInstaller::inflectExtensionVars() should return array<string, string> but returns array<string, string|null>.
[104](https://github.com/composer/installers/runs/5038318637?check_suite_focus=true#step:7:104)
Error: Process completed with exit code 1.

May be you will try change phpDocs for inflectExtensionVars()? Returned values and phpDocs isn't compatibility.

[sampoyigi]

Thanks, got it passing now, is there anything else I can do here?