feat(mise): add support for github backend

[oschwald]

Changes

This pull request adds support for the mise github backend. This is similar to the ubi backend except the version constraints allowed for it seem to be more limited.

Context

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• This closes an existing Issue, Closes: #
• This doesn't close an Issue, but I accept the risk that this PR may be closed if maintainers disagree with its opening or implementation

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• Newly added/modified unit tests, or
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The public repository:

I tested it against our internal GitHub Enterprise Server instance.

[cla-assistant]

All committers have signed the CLA.

[viceice]

otherwise LGTM

[viceice]

I don't like that, it causes performance loose when it's not needed. it should be configured explicit if needed. 🤔

[oschwald]

This was inspired by the ubi backend. The aqua backend seems to always use extractVersion. Could you expand a bit on what your preferred solution might look like?

[RahulGautamSingh]

Isn't this already covered in the previous test?

[RahulGautamSingh]

Suggested change

	// Empty prefix - no extractVersion needed if version has 'v'
	// Empty prefix - no extractVersion needed if version starts with 'v'

[RahulGautamSingh]

Less nested ifs

Suggested change

	if (isString(toolOptions.version_prefix)) {
	const prefix = toolOptions.version_prefix;
	if (prefix === '') {
	// Empty prefix - no extractVersion needed if version has 'v'
	if (!hasVPrefix) {
	extractVersion = '^(?<version>.+)';
	}
	} else {
	// Custom prefix - escape special regex chars
	const escapedPrefix = prefix.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
	extractVersion = `^${escapedPrefix}(?<version>.+)`;
	}
	} else if (!hasVPrefix) {
	// Default: strip 'v' prefix if current version doesn't have it
	extractVersion = '^v?(?<version>.+)';
	}
	if (isNonEmptyString(prefix)) {
	// Custom prefix - escape special regex chars
	const escapedPrefix = prefix.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
	extractVersion = `^${escapedPrefix}(?<version>.+)`;
	}
	// Empty prefix - no extractVersion needed if version has 'v'
	if (isEmptyString(prefix) && !hasVPrefix) {
	extractVersion = '^(?<version>.+)';
	}
	if (!hasVPrefix) {
	// Default: strip 'v' prefix if current version doesn't have it
	extractVersion = '^v?(?<version>.+)';
	}

[oschwald]

Although this seems a bit more performance intensive, I modified it. I did need to switch to else if to prevent the last if from overwriting extractVersion if it was set earlier. I could have an explicit check instead though if you prefer that.

[RahulGautamSingh]

LGTM

[oschwald]

Do you want me to rebase and force push? I see there is now a conflict.

[oschwald]

I rebased this. Please let me know if there is anything else that needs to be changed.