Add CHANGELOG entry for EMF Lambda dimensions feature

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Co-Authored-By: Claude <[email protected]>

Author: syed-ahsan-ishtiaque

CHANGELOG.md

@@ -11,6 +11,8 @@ For any change that affects end users of this package, please add an entry under
 If your change does not need a CHANGELOG entry, add the "skip changelog" label to your PR.
 
 ## Unreleased
+- Add Service and Environment dimensions to EMF metrics for Lambda
+  ([#548](https://github.com/aws-observability/aws-otel-python-instrumentation/pull/548))
 - Add Resource and CFN Attributes for Bedrock AgentCore spans
   ([#495](https://github.com/aws-observability/aws-otel-python-instrumentation/pull/495))
 - Add botocore instrumentation extension for Bedrock AgentCore services with span attributes