assert.file is not case sensitive

[mjungwir]

I discovered with a test that failed on a build server and passed locally that the underlying fs.existsSync depends on the OS' case sensitivity. I know this project won't be addressing the fs methods but I was wondering if there was any discussion to be had around finding a way to opt in or out of asserting files with case sensitivity.

[JoshuaKGoldberg]

👍 I think this is a reasonable feature request. Case sensitivity is a pain to debug if something is off. I think it'd make sense to mark this as accepting add a third parameter to assert.file & similar methods for options. That parameter can start with a single property like caseSensitive?: boolean.

WDYT @UlisesGascon?