fix: sigv4 README.md brackets (#1103)

Author: kuhe

.changeset/loud-clouds-call.md

@@ -0,0 +1,5 @@
+---
+"@smithy/signature-v4": patch
+---
+
+fix readme brackets

packages/signature-v4/README.md

@@ -3,7 +3,7 @@
 [![NPM version](https://img.shields.io/npm/v/@smithy/signature-v4/latest.svg)](https://www.npmjs.com/package/@smithy/signature-v4)
 [![NPM downloads](https://img.shields.io/npm/dm/@smithy/signature-v4.svg)](https://www.npmjs.com/package/@smithy/signature-v4)
 
-This package contains an implementation of the (AWS Signature Version 4)[https://docs.aws.amazon.com/AmazonS3/latest/API/sig-v4-authenticating-requests.html]
+This package contains an implementation of the [AWS Signature Version 4](https://docs.aws.amazon.com/AmazonS3/latest/API/sig-v4-authenticating-requests.html)
 authentication scheme.
 
 It is internal to Smithy-TypeScript generated clients, and not generally intended for standalone usage outside this context.