fix: remove deprecated lodash per-method packages for vulnerability fixes

[EmilianoSanchez]

• Removed lodash per-method packages, like lodash.eq and lodash.indexOf, which are discouraged, deprecated, and a source of potential security vulnerabilities: https://lodash.com/per-method-packages (Examples of reported vulnerabilities in lodash per-method packages: Wrong version in lodash.pick vulnerability report CVE-2020-8203 lodash/lodash#5809, Please republish lodash.forin  lodash/lodash#5808).

• Replaced the import of lodash per-method packages with direct imports, as suggested here.

[folkvir]

It would be very appreciated if you could submit your PR into #76 for the major update.
Also there are other involved lodash packages for the tests, if you could also update them 👍

[EmilianoSanchez]

Thanks @folkvir. I did the changes using direct imports (e.g., import eq from 'lodash/eq').
Another option was to use top-level imports (e.g., import {eq} from 'lodash'), although I think the former is better for tree-shaking, according to https://lodash.com/per-method-packages.