ESLint can enforce this for us with the built-in "eqeqeq" rule, which
you might not know about if you'd search for "strict", "equality" or
"equal" in the rules list.

Idea is to avoid coercion due to `==`/`!=` which can be a source of
bugs, except in the case of `null`, where `x == null` is a convenient
and idiomatic shorthand for `x === null || x === undefined` (you can
still do an explicit `x === null` check if that's what you want).

Docs: https://eslint.org/docs/rules/eqeqeq

Closes: https://github.com/liferay/eslint-config-liferay/issues/158

docs: Add branch structure guidelines (#9)