allow anonymous AWS access

[melugoyal]

allow anonymous AWS access. this allows the consumer of any AWS operator to use the equivalent of aws s3 cp <s3 path> . --no-sign-request, to write a DAG that eg reads from a public S3 bucket without providing any credentials. to leverage this, an AWS connection can be created as such:

conn = Connection(
    conn_id="aws_demo",
    conn_type="aws",
    extra={
        "config_kwargs": {
            "signature_version": "unsigned",
        },
    },
)

this is necessary because botocore's UNSIGNED is not JSON-serializable, so using botocore.UNSIGNED when instantiating the connection will cause the connection processing to fail. instead we can use a string in the connection instantiation and convert it to botocore's expected value later. more history about this issue here: boto/botocore#2442

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[vincbeck]

LGTM

[jedcunningham]

Overall looks good. Should we document this somehow as well?

[vincbeck]

Overall looks good. Should we document this somehow as well?

Good callout! I'd say yes :)

[melugoyal]

@jedcunningham @vincbeck good call. added a sentence to the AWS connection docs. lmk how that looks

[o-nikolas]

Other than the static check failures, lgtm 👍

[jedcunningham]

@melugoyal I'd suggest you set up the pre-commit hooks, they help catch these issues early 👍.

[boring-cyborg]

Awesome work, congrats on your first merged pull request! You are invited to check our Issue Tracker for additional contributions.

[jedcunningham]

Thanks @melugoyal! Congrats on your first commit 🎉