fix: object properties, func, and so on must not convert to camelCase

[yutak23]

This ought to fix #111. And also fix #77.

I think the reason why even fields/methods of classes and object are converted to camelCase is because of the use of Record<string, any>.
Record<string, any> means { [P in string]: any; }. This type definition uses any, so it will be true as follows.

// type result is 'true'(Date extends Record<string, any>)
type result = Date extends Record<string, any> ? 'true' : 'false';

Therefore, I think the problem can be solved by not using Record<string, any> and using Record<string, unknown> instead.

The rationale is as follows.
https://github.com/Microsoft/TypeScript/wiki/Breaking-Changes#-k-string-unknown--is-no-longer-a-wildcard-assignment-target

[yutak23]

I have version up because following issue error (on local testing).

xojs/xo#718

[yutak23]

This has been added in this PR, which is essentially a Record<string, any>, which would have been {} due to the fact that it is a Record<string, any>. This change to unknow makes this condition unnecessary.

// type result is 'true'
type testType<T> = T extends Record<string, any> ? 'true' : 'false';
type result = testType<() => 123>;

[yutak23]

To support optional properties.
This change allows the following tests to pass.

expectType<ConvertedDeepObjectDataTypeWithDeepTrue>(
	camelcaseKeys(deepInputData, {deep: true}),
);

[yutak23]

@sindresorhus

I would appreciate it if you could check the PR to fix the bug when used with TypeScript.