[X] bug report
[ ] feature request

# Detailed description

The AWS API supports Authorization parameters as GET parameters, e.g. here's a GET request to SendMessage on SQS:

```
curl 'http://localhost:4566/000000000000/SomeQueue.fifo?Action=SendMessage&MessageGroupId=Default&MessageDeduplicationId=1615597859837&MessageBody=%7B%22gateway_id%22%3A%20%2204e73c80-3539-499c-92a4-a0b106c2f6ab%22%7D&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=test%2F20210313%2Fus-east-1%2Fsqs%2Faws4_request&X-Amz-Date=20210313T011059Z&X-Amz-Expires=86400000&X-Amz-SignedHeaders=host&X-Amz-Signature=2c652c7bc9a3b75579db3d987d1e6dd056f0ac776c1e1d4ec91e2ce84e5ad3ae'
```

## Expected behavior

Should send the message and return receipt information.

## Actual behavior

Returns...

```
<?xml version="1.0" encoding="UTF-8"?>
<Error>
    <Code>NoSuchBucket</Code>
    <Message>The specified bucket does not exist</Message>
    <BucketName>000000000000</BucketName>
    <RequestID>7a62c49f-347e-4fc4-9331-6e8eEXAMPLE</RequestID>
</Error>
```

""" A context manager that captures stdout/stderr of the current thread. Use it as follows:
        with CaptureOutput() as c:
            ...
        print(c.stdout(), c.stderr())
    """
    orig_stdout = sys.stdout
    orig_stderr = sys.stderr
    orig___stdout = sys.__stdout__
    orig___stderr = sys.__stderr__
    CONTEXTS_BY_THREAD = {}
    class LogStreamIO(io.StringIO):
        def write(self, s):
            if isinstance(s, str) and hasattr(s, 'decode'):
                s = s.decode('unicode-escape')
            return super(CaptureOutput.LogStreamIO, self).write(s)
    def __init__(self):
        self._stdout = self.LogStreamIO()
        self._stderr = self.LogStreamIO()
    def __enter__(self):
        
        from werkzeug.local import LocalProxy
        ident = self._ident()
        if ident not in self.CONTEXTS_BY_THREAD:
            self.CONTEXTS_BY_THREAD[ident] = self
            self._set(LocalProxy(self._proxy(sys.stdout, 'stdout')),
                      LocalProxy(self._proxy(sys.stderr, 'stderr')),
                      LocalProxy(self._proxy(sys.__stdout__, 'stdout')),
                      LocalProxy(self._proxy(sys.__stderr__, 'stderr')))
        return self
    def __exit__(self, type, value, traceback):