Examples not loading due to API key

[IvanSanchez]

The examples linked from the readme (e.g. https://raw.githack.com/maplibre/maplibre-gl-leaflet/main/examples/basic.html ) all fail to load.

I can see the following error message in my browser's console:

Error: AJAXError: Forbidden (403): https://api.maptiler.com/maps/topo/style.json?key=[snip]

...which tells me the Maptiler API key has expired, or has the wrong referrers set up.

[wipfli]

@klokan