dev-cmd/bump: fix comparison of versions with comma-separated values

[khipp]

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This PR fixes an issue when running brew bump with casks that use version stanzas containing comma-separated values.

The problem occurs when the number of components increases (e.g., 9.5,286 ==> 9.5.1,287), since the versions are compared token by token, leading to incorrect results (e.g., 1 < 286).
To resolve this, instances of LivecheckVersion are used to split the comma-separated values into individual Version objects.

Before:

$ brew bump --cask banktivity
==> banktivity
Current cask version:     9.5,286
Latest livecheck version: unable to get versions
...

After:

$ brew bump --cask banktivity
==> banktivity
Current cask version:     9.5,286
Latest livecheck version: 9.5.1,287
...

Related to Homebrew/homebrew-cask#182564.

[samford]

Nice catch. Your explanation makes sense to me (Version ignores delimiters when doing comparisons, so . and , are treated the same) and this fix worked as expected when tested locally.

Thanks, @khipp!