fix: disallow uppercase in package name

[amrbashir]

closes #523

What kind of change does this PR introduce?

• Bugfix
• Feature
• Docs
• New Binding issue #___
• Code style update
• Refactor
• Build-related changes
• Other, please describe:

Does this PR introduce a breaking change?

• Yes, and the changes were approved in issue #___
• No

Checklist

• When resolving issues, they are referenced in the PR's title (e.g fix: remove a typo, closes #___, #___)
• A change file is added if any packages will require a version bump due to this PR per the instructions in the readme.
• I have added a convincing reason for adding this feature, if necessary

Other information

[FabianLars]

Is that only for the name in package.json and cargo.toml? Because tauri.conf's product name does support this (and spaces)

[amrbashir]

This affects product name as well but that was the old behavior anyways of CTA, i.e. previously if it had spaces, it would be removed.

[amrbashir]

I will open another PR to keep spaces and uppercase in productName