fix: examples for tokio

[jpopesculian]

Examples wouldn't compile because of

• Not having the required features
• futures version being outdated

In addition, I added an example for tokio-tungstenite and renamed some examples for clarity and typos

[obmarg]

What compile errors were you seeing without these changes?

I build & test the examples on CI so it's a little worrying if that's not working...

[jpopesculian]

Locally on main, if I run

cargo run --example tokio

the trait bound `StreamingOperation<BooksChangedSubscription>: GraphqlOperation` is not satisfied
  --> examples/examples/tokio.rs:60:39

cargo run --example cynic-mulitiple-subscriptions

error[E0277]: the trait bound `StreamingOperation<BooksChangedSubscription>: GraphqlOperation` is not satisfied
  --> examples/examples/cynic-mulitiple-subscriptions.rs:63:51

cargo run --example graphql-client-single-subscription

error[E0432]: unresolved import `graphql_ws_client::graphql::StreamingOperation`
  --> examples/examples/graphql-client-single-subscription.rs:8:5

cargo run --example cynic-single-subscription

error[E0277]: the trait bound `StreamingOperation<BooksChangedSubscription>: GraphqlOperation` is not satisfied
   --> examples/examples/cynic-single-subscription.rs:56:20

Adding features client-cynic and client-graphql-client fixes those errors. I was also encountering an issue with the futures crate for some reason sticking to futures 0.3.28 when I added tokio-tungstenite so I pinned it to at least 0.3.31 (the other versions are yanked)