Location of the layers schema is incorrect in the Maven Plugin's examples

[wilkinsona]

We've got this at the moment:

<layers xmlns="http://www.springframework.org/schema/boot/layers"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://www.springframework.org/schema/boot/layers
                            layers-xsd: https://www.springframework.org/schema/boot/layers/layers-3.3.xsd">

I think the layers-xsd: is incorrect and it should be the following:

<layers xmlns="http://www.springframework.org/schema/boot/layers"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://www.springframework.org/schema/boot/layers
                            https://www.springframework.org/schema/boot/layers/layers-3.3.xsd">

This would then align with what we've got in the 3.2 docs.