Failed to build with only feature dynamodb

[bryanburgers]

In version 0.7.0 released recently, specifying only the dynamodb feature fails to build. This previously worked fine in 0.6.0.

This is reproducible with the following sequence of commands.

$ git clone https://github.com/LegNeato/aws-lambda-events
$ cd aws-lambda-events
$ git switch -d v0.7.0
$ cargo build --no-default-features --features dynamodb
error[E0432]: unresolved import `crate::event::streams`
 --> aws_lambda_events/src/dynamodb/mod.rs:2:19
  |
2 | use crate::event::streams::DynamoDbBatchItemFailure;
  |                   ^^^^^^^ could not find `streams` in `event`

Building with dynamodb and events seems to work fine.

$ cargo build --no-default-features --features dynamodb --features events

I ran into this because serde_dynamo only needs enough of aws-lambda-events to bring AttributeValue into scope.

For 0.6.0, the Cargo.toml invocation I used was

__aws_lambda_events_0_6 = { package = "aws_lambda_events", version = "0.6", default-features = false, features = ["dynamodb"], optional = true }

which fails for 0.7.0.

At this point I think I'll just use features = ["dynamodb", "events"] to support the already published 0.7.0, but I thought I'd bring it up as an issue in case you felt it needed to be addressed?