feat: add query for group events

[ifranco14]

I've finally found Meetup's GraphQL Playground, it's not the best I've seen (the schema doesn't load and you cannot use it outside meetup page, e.g. using the endpoint in https://www.graphqlbin.com/v2/new or other online playgrounds). At least it works to try out the queries.

In the current query both upcomingEvents and eventSearch fields are request. @astrojuanlu I leave on you the decision on which to use, IMHO we could go for eventSearch so as to enable ourself to define what an upcoming event is.

Finally, the node.id field is the id of the event that will be used later to call query_event

Example:

[ifranco14]

TODO in the following PRs:

• add a method to read the communities and query for their events
• refactor both existing methods to receive the token so as to avoid authenticating twice
• return a (pydantic?) model instead of dicts

[ifranco14]

Thanks for the review @astrojuanlu, I'll add the changes during the week.

BTW, did you see the TODO list that I added as a comment? Should we move it to the readme and add the rest that's missing? Do you agree with it?

TODO in the following PRs:

• add a method to read the communities and query for their events
• refactor both existing methods to receive the token so as to avoid authenticating twice
• return a (pydantic?) model instead of dicts

[astrojuanlu]

Right! I think we could

• add a method to read the communities and query for their events, and
• refactor both existing methods to receive the token so as to avoid authenticating twice

about the models (pydantic, dataclass, or anything else) we could wait for another PR. do you agree?

[ifranco14]

Sorry for the confusion, my intention is for all them to be done in different, small and very well scoped pull requests, which will also make the review of the code much easier :)

Good to know that we're on the same page then, I'll finish this one and then once it's merged I'll start working on the following step in the TODO list in a new PR.