Update ESLint to 7.5.0

[NemoStein]

The recently released ESLint 7.5.0 introduces support for the Optional Chaining operator, while ESLint 7.2.0 already introduced support for the Nullish Coalescing operator.

Integrating this changes would allow us, developer, to use those new operators without been bombarded by Standard syntax parser errors.

[NemoStein]

Additionally, enabling rules no-promise-executor-return and no-unreachable-loop, added in ESLint 7.3.0, might be a good idea.

Also, no-loss-of-precision (ESLint 7.1.0) and sort-imports (--fix rule, ESLint 7.5.0) can be a good QoL addition.

[shadowspawn]

Existing standard issue is: #1518

[feross]

We're upgrading to ESLint 7.11.0 in standard v15, which will be released later today!