gts check enforces eol=lf on Windows

This one may be WAI because gts is supposed to be opinionated. But with default git settings, which instruct git to automatically convert LF to CRLF for `text` files on Windows, it is not working well out of the box. More about this in https://eslint.org/docs/rules/linebreak-style#using-this-rule-with-version-control-systems ("Using this rule with version control systems" section).

Anyway, if the intention is to leave the enforcement with "unix", maybe you'd like to add this link to README?

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For posterity: I'm getting these errors from our CI which builds on Windows (btw -- doesn't happen on Mac builds):

```
src\index.ts
##[error] 1:48 error Delete `␍` prettier/prettier
##[error] 2:50 error Delete `␍` prettier/prettier
##[error] 3:50 error Delete `␍` prettier/prettier
##[error] 4:26 error Delete `␍` prettier/prettier
##[error] 5:28 error Delete `␍` prettier/prettier
...
```