* feat: pull country or language by code.
This differs from the existing `search` functionality in that it allows
you to explicitly pull back a single country or language instead of
anything that matches (which could result in more items returned than
expected).
* refactor(types): add new types for the affected endpoints.
* docs(readme): update to include examples for new functionality.
* test: expand tests to include new parameters.
* feat(package): upgrade dependencies to the latest versions.
* fix(eslint): adjust configuration based on an updated dependency.
* docs(license): bump the year of the license.
