fix packaging of the layer artifacts (aws-observability#993)

The current logic is including the full path of the
`aws-opentelemetry-javaagent.jar` in the zip. But it should be at the
root along-with the `otel-instrument` file.

Tested locally and verified the directory structure is now correct.


By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 license.

Author: srprash

lambda-layer/build-layer.sh

@@ -49,7 +49,10 @@ echo "Info: Building ADOT Lambda Java SDK Layer Code"
 echo "Info: Creating the layer artifact"
 mkdir -p "$SOURCEDIR"/build/distributions/
 cp "$SOURCEDIR"/build/javaagent/aws-opentelemetry-agent*.jar "$SOURCEDIR"/build/distributions/aws-opentelemetry-javaagent.jar
-zip -r ./build/distributions/aws-opentelemetry-java-layer.zip "$SOURCEDIR"/build/distributions/aws-opentelemetry-javaagent.jar otel-instrument
+cp otel-instrument "$SOURCEDIR"/build/distributions/otel-instrument
+pushd "$SOURCEDIR"/build/distributions
+zip -r aws-opentelemetry-java-layer.zip aws-opentelemetry-javaagent.jar otel-instrument
+popd
 
 ## Cleanup
 # revert the patch applied since it is only needed while building the layer.