Tests: Improve Windows compatibility (#249)

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Use wp_update_image_subsizes() for --only-missing on WP 5.3+ (#236)

Co-authored-by: swissspidy <841956+swissspidy@users.noreply.github.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>

PHPStan level 9 (#229)

* PHPStan level 9

* Update src/Media_Command.php

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Update src/Media_Command.php

* Update src/Media_Command.php

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Update src/Media_Command.php

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Update src/Media_Command.php

* More fixes

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Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Fix field order in test

Update file(s) from wp-cli/.github

Merge pull request #213 from wp-cli/refine-feature-files

Merge pull request #205 from wp-cli/no-lock-file

Merge pull request #199 from wp-cli/fix/111-only-delete-unknown

Merge pull request #192 from ernilambar/116-fix-image-size

Add `--file_name=<name>` argument for `wp media import` (#187)

* Added slug option for media

* Changed slug to file_name

* Added functional test

* Tweak success output

Co-authored-by: Alain Schlesser <alain.schlesser@gmail.com>

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Co-authored-by: Daniel Bachhuber <daniel@bachhuber.co>
Co-authored-by: Alain Schlesser <alain.schlesser@gmail.com>