fix eslint config for version 6.*

[mgred]

• fix eslint config to use an array as pointed out in eslint: overrides should be a list #14
• pin the version of eslint to 6.*
• fix some error from lint-staged config which occured as well

[coveralls]

Pull Request Test Coverage Report for Build 64

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

---

Totals
Change from base Build 60:	0.0%
Covered Lines:	72
Relevant Lines:	72

---

💛 - Coveralls

[mgred]

BTW, we use this kind of config in all our Projects. @mroderick do you think we should update this everywhere?

[mantoni]

We actually have a shared eslint-config project. I don't know why it's not (yet?) used here … EDIT: Just saw that it is being used. Sry.

It has eslint 5 as a peer dependency here which we could bump to 6, release a major and then include it here as well (see https://github.com/sinonjs/eslint-config-sinon/blob/e91b0b2b9a6aff769f8a03211c36d955147eff16/package.json#L10-L11).

[mroderick]

It has eslint 5 as a peer dependency here which we could bump to 6, release a major and then include it here as well (see https://github.com/sinonjs/eslint-config-sinon/blob/e91b0b2b9a6aff769f8a03211c36d955147eff16/package.json#L10-L11).

We should probably also go over all the rules and see if any have been removed/deprecated, and see if there are new rules that we may want.

Once next major eslint-config-sinon is out, we can rebase this branch, and merge it!

[mroderick]

eslint-config-sinon@3.0.0 is out.

Please update this PR to use that

[mgred]

done @mroderick

[mroderick]

Looking good 👍

[mgred]

thanks 👍