Add only_args action argument

[reflexxion]

Using the php-actions/composer@v2 action for other commands than install or update will currently make it hard configuring the desired action.

To e.g. call the dump-autoload command it is currently necessary to "enable" some options so that they won't be appended to the final composer call. (and fail otherwise because they aren't supported by some commands)
Like so:

            -  uses: php-actions/composer@v2
                with:
                    command: dump-autoload
                    dev: no
                    suggest: yes # We need to set this setting because --no-suggest will be appended otherwise and the command will fail
                    progress: yes # We need to set this setting because --no-progress will be appended otherwise and the command will fail
                    args: --classmap-authoritative

To easily configure this options I've implemented an only_args argument which will disable all other action arguments.
So the desired dump-autoload command can be generated by:

            -  uses: php-actions/composer@v2
                with:
                    command: dump-autoload
                    only_args: --no-dev --no-interaction --classmap-authoritative

[g105b]

Hi @reflexxion ,

Thanks so much for your first contribution to this repo. I see the problem you've outlined and will test out your PR in the Example Composer repository to see that it works under some circumstances.

Great to have you on board!