[4.x] Add contextual rules

[nunomaduro]

TL;DR: The condition field on rules is now optional.

Actions required:

• Update the cts with the information on : #71

• On strongly typed clients, update types in query rules, as the condition field in rules is now optional

• Python test suite update

[nunomaduro]

Closed as pull request as made here: DefinitelyTyped/DefinitelyTyped@master...Haroenv:patch-3.

[Haroenv]

that's not a PR yet, because it's not yet released, so can't be published yet :)

[nunomaduro]

Make the following pull request once the feature is released : DefinitelyTyped/DefinitelyTyped@master...Haroenv:patch-3.

Body of the pull request described here: https://github.com/algolia/algoliasearch-client-specs-internal/issues/42

[nunomaduro]

Done on the v4.