Update SDK and Lambda Layer Release Workflows to Add layer.zip Artifacts (#1038)

*Description of changes:*
Same as:
aws-observability/aws-otel-python-instrumentation#335
and
aws-observability/aws-otel-python-instrumentation#337

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

Author: yiyuan-he

.github/workflows/release-build.yml

@@ -129,9 +129,17 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} # This token is provided by Actions, you do not need to create your own token
         run: |
+          # Download layer.zip from existing latest tagged SDK release note
+          LATEST_SDK_VERSION=$(gh release list --repo "aws-observability/aws-otel-java-instrumentation" --json tagName,isLatest -q 'map(select(.isLatest==true)) | .[0].tagName')
+          mkdir -p layer_artifact
+          gh release download "$LATEST_SDK_VERSION" --repo "aws-observability/aws-otel-java-instrumentation" --pattern "layer.zip" --dir layer_artifact
+          shasum -a 256 layer_artifact/layer.zip > layer_artifact/layer.zip.sha256
+
           gh release create --target "$GITHUB_REF_NAME" \
              --title "Release v${{ github.event.inputs.version }}" \
              --draft \
              "v${{ github.event.inputs.version }}" \
              ${{ env.ARTIFACT_NAME }} \
-             ${{ env.ARTIFACT_NAME }}.sha256
+             ${{ env.ARTIFACT_NAME }}.sha256 \
+             layer_artifact/layer.zip \
+             layer_artifact/layer.zip.sha256

.github/workflows/release-lambda.yml

@@ -224,3 +224,13 @@ jobs:
              layer_arns.tf layer.zip
           echo Removing release_notes.md ...
           rm -f release_notes.md
+      - name: Upload layer.zip and SHA-256 checksum to SDK Release Notes (tagged with latest)
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          LATEST_SDK_VERSION=$(gh release list --repo "aws-observability/aws-otel-java-instrumentation" --json tagName,isLatest -q 'map(select(.isLatest==true)) | .[0].tagName')
+          # Generate SHA-256 checksum for layer.zip
+          shasum -a 256 layer.zip > layer.zip.sha256
+          # Upload layer.zip and its checksum to the latest SDK release note
+          gh release upload "$LATEST_SDK_VERSION" layer.zip layer.zip.sha256 --repo "aws-observability/aws-otel-java-instrumentation" --clobber
+          echo "✅ layer.zip successfully uploaded to $LATEST_SDK_VERSION in the upstream repo!"