Make size(arr, tohighdimension) return 1

[felixcremer]

This makes size(zarr, dimnum= return 1 for to large dimensions numbers and give a better error message for negative dimension numbers.

This is needed so that concatenation of cubes backed by a Zarr array still work in DiskArrays after
JuliaIO/DiskArrays.jl#280

[coveralls]

Pull Request Test Coverage Report for Build 19540979232

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.

• For more information on this, see Tracking coverage changes with pull request builds.
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• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 6 of 6 (100.0%) changed or added relevant lines in 1 file are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage increased (+0.06%) to 89.348%

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Files with Coverage Reduction	New Missed Lines	%
src/metadata.jl	1	92.05%

Totals
Change from base Build 18793430184:	0.06%
Covered Lines:	973
Relevant Lines:	1089

---

💛 - Coveralls

[felixcremer]

The nightly failures are an unrelated Pkg loading of precompiled packages problem and the codecov check is just strange. Because on codecov itself it looks as if all lines are hit.

[nhz2]

Looks good. Though a more basic error message without string interpolation might slightly improve performance.