Fix a typo in generating URL for us-based regions

[grishick]

First of all, thank you for creating this package! I was using it today and I was getting errors until I realized that there is a typo in how S3 URL is being generated for non-Chinese based regions. With this fix, the package works w/o custom URL on non-Chinese regions.

[jplindgren]

Thanks for your PR man. It saved me a lot of time. I was not setting the s3Url and did not realize that the URL generated was wrong.
Please, guys, review this PR when you can because it can help a lot of people.

[martinrojas]

Is this going to be merged at any point?

[rjcd95]

It's ok based on documentation

[luciancic]

Thx for the fix and for the info. Just to outline the workaround for everyone while we wait for this get merged:

const bucketName = "my-bucket";
const region = "us-east-1";
const config = {
  bucketName,
  region,
  accessKeyId: "my-access-key-id",
  secretAccessKey: "my-secret-access-key",
  // this is the required line to fix your error
  s3Url: `https://${bucketName}.s3.${region}.amazonaws.com`,
};

const ReactS3Client = new S3(config);
// etc.