Update maps column view to allow the use of placeholders

[ryanmortier]

FilamentGoogleMaps\Columns\MapColumn::make('coordinates')
    ->label('Map')
    ->type('hybrid')
    ->alignCenter()
    ->zoom(14)
    ->height(100)
    ->width(150)
    ->placeholder(fn (): HtmlString => new HtmlString('—')),

Preview:

[Heyian]

Hey there. I've merged this PR onto my fork so we can all get all these goodies from a single place. I gave credits to the person who made the PR in the commits, changelog and in the releases.
I've also credited cheesegrits for his work on the repo and made it clear this was a fork on top of the Readme. I'm not trying to hijack anything, I just want to be able to use all the good solutions people put in the pull requests and I thought I'd made this available to all. If you're interested in this version or want to contribute, you can find my fork at : Heyian/forkMain

I'm open to suggestions on how to move forward from here, simply open up an issue in my fork so we can chat about it.
Thanks.

[cheesegrits]

@ryanmortier

Hey, I'm working with @Heyian to get this package whipped back in to shape. I've had some serious medical issues this year which have kept me from working on it, but I'm recovered now.

Thanks for the PR.

Can you update the README to document this, then I'll merge it.