Update action.yml to support changing the assumed project directory

[daerogami]

From issue #2:

Also, is this a stand-alone script or should this be in my godot project's scripts folder? because my project is inside a folder named src, so unless there is a way to tell the Apply version to export information step to change its working directory, there are file path assumptions that won't work with my project being inside a folder instead of the root of the repo.

[jonjondev]

I would double check whether leaving the default value as blank will provide the same functionality as .\, but otherwise the looks fine to merge. Please update the documentation to include the new input parameter for build-godot and we can proceed from there.

Note that you will need to rebase on top of latest changes on main - please do not add a merge-commit.

[daerogami]

Thanks Jon! Will take a look at this between today or tomorrow.