New rules for next major release

The following are low priority rules to add to the next major release (but don't drive a major release themselves):

• https://eslint.org/docs/rules/no-promise-executor-return (new in 7.3.0)
• https://eslint.org/docs/rules/no-unreachable-loop (new in 7.3.0)
• https://github.com/jest-community/eslint-plugin-jest/blob/master/docs/rules/no-conditional-expect.md (new in 23.16.0)