Allow to pass region as parameter in connection string

[funny-falcon]

It is a bit cumbersome to specify region when it is not specified in environment variable, and there is no reason to not allow it to be passed in connection string, imho.

[tejasmanohar]

@funny-falcon Untested, but I think the below code does what you want. Should it be in the README?

db, err := athena.Open(Config{
  Session: session.Must(session.NewSession(&aws.Config{
    Region: aws.String("YOUR AWS REGION"),
  }))
})

// db is a sql.DB

FWIW, I'm ok supporting more options in the connection string, but I think we should support the three most common options to avoid more PRs :) 1) aws_access_key_id 2) aws_secret_access_key 3) aws_region

If you decide to update the PR, please also update the godoc comment on Driver.Open().

[tejasmanohar]

If you're feeling generous (optional), I think a quick section in the README explaining the 3 different ways (env, creds in connection string, athena.Open()) to authenticate with AWS would help, too 😄

[funny-falcon]

access_key_id and secret_access_key are "dangerous". And they could be set at EC2 level. region is safe, and could not be set at EC2 level (amazon, why? the most stupid decision, I think) May I not add access_key and secret_access_key ?

Untested, but I think the below code does what you want. Should it be in the README?

Certainly

[tejasmanohar]

SGTM. We don't use raw AWS keys either. Merging.

[tejasmanohar]

And as always, thanks for contributing