Overload Base.UInt8 explicitly

[felixcremer]

This would hopefully get rid of the following warning in julia 1.12

 ┌ Zarr
│  WARNING: Constructor for type "UInt8" was extended in `Zarr` without explicit qualification or import.
│    NOTE: Assumed "UInt8" refers to `Base.UInt8`. This behavior is deprecated and may differ in future versions.`
│    NOTE: This behavior may have differed in Julia versions prior to 1.12.
│    Hint: If you intended to create a new generic function of the same name, use `function UInt8 end`.
│    Hint: To silence the warning, qualify `UInt8` as `Base.UInt8` in the method signature or explicitly `import Base: UInt8`.
└  

[mkitti]

I slipped a commit like this into #182 , but yes, doing this independently is best.

[coveralls]

Pull Request Test Coverage Report for Build 14908265411

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

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Details

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.08%) to 85.957%

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Totals
Change from base Build 13680422725:	-0.08%
Covered Lines:	912
Relevant Lines:	1061

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💛 - Coveralls

[mkitti]

Looks good to me.