docs: updating the README.md for the metrics module.

Author: msailes

README.md

@@ -2,7 +2,7 @@
 
 ![aws provider](https://img.shields.io/badge/provider-AWS-orange?logo=amazon-aws&color=ff9900)
 
-A suite of utilities for AWS Lambda Functions that makes tracing with AWS X-Ray, structured logging and creating custom metrics asynchronously(Coming soon!) easier.
+A suite of utilities for AWS Lambda Functions that makes tracing with AWS X-Ray, structured logging and creating custom metrics asynchronously easier.
 
 **[📜Documentation](https://awslabs.github.io/aws-lambda-powertools-java/)** | **[Feature request](https://github.com/awslabs/aws-lambda-powertools-java/issues/new?assignees=&labels=feature-request%2C+triage&template=feature_request.md&title=)** | **[🐛Bug Report](https://github.com/awslabs/aws-lambda-powertools-java/issues/new?assignees=&labels=bug%2C+triage&template=bug_report.md&title=)** | **[Detailed blog post](https://aws.amazon.com/blogs/opensource/simplifying-serverless-best-practices-with-lambda-powertools/)**
 
@@ -24,6 +24,11 @@ Powertools is available in Maven Central. You can use your favourite dependency
         <artifactId>powertools-logging</artifactId>
         <version>0.2.0-beta</version>
     </dependency>
+    <dependency>
+        <groupId>software.amazon.lambda</groupId>
+        <artifactId>powertools-metrics</artifactId>
+        <version>0.2.0-beta</version>
+    </dependency>
     ...
 </dependencies>
 ```
@@ -51,6 +56,10 @@ And configure the aspectj-maven-plugin to compile-time weave (CTW) the aws-lambd
                          <groupId>software.amazon.lambda</groupId>
                          <artifactId>powertools-tracing</artifactId>
                      </aspectLibrary>
+                     <aspectLibrary>
+                         <groupId>software.amazon.lambda</groupId>
+                         <artifactId>powertools-metrics</artifactId>
+                     </aspectLibrary>
                  </aspectLibraries>
              </configuration>
              <executions>