Use Utils\make_temp_file() and Utils\make_temp_dir() for temporary paths #249

wp-cli/wp-cli#6374 added Utils\make_temp_file() and Utils\make_temp_dir() (merged to main, milestone 3.0.0). src/Package_Command.php still builds temporary paths by hand:

• line 279: Utils\get_temp_dir() . uniqid( 'wp-cli-package_', true ) . '.zip' for the downloaded ZIP
• line 294: Utils\get_temp_dir() . uniqid( 'wp-cli-package_', true ) for the extraction directory

Switch them to Utils\make_temp_file( 'wp-cli-package_', '.zip' ) and Utils\make_temp_dir( 'wp-cli-package_' ). Two things to check on the way: make_temp_dir() creates the directory (mode 0700) before Extractor::extract() runs, so the extractor gets an existing empty directory instead of creating it, and it returns the path with a trailing slash, which the later get_package_name_and_version_from_dir_package(), copy_overwrite_files() and rmdir() calls receive.

Blocked on a wp-cli/wp-cli release that ships the helpers. composer.json already requires wp-cli/wp-cli ^3.0.