feat: add linux support to bump-cask-pr

[SMillerDev]

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This will allow bump and bump-* commands to update linux casks.

[MikeMcQuaid]

Looks good, thanks! How would this work to call it to bump e.g. a package with macOS and Linux binaries?

[SMillerDev]

How would this work to call it to bump e.g. a package with macOS and Linux binaries?

I didn't adjust any of the special cases, but I tested it by resetting my cask install and running brew bump-cask-pr --version=0.77.0 wizcli --write-only which updated all the shasum values.