fix(ci): create one layer artifact per region & merge (#3808)

Author: heitorlessa

.github/workflows/publish_v2_layer.yml

@@ -257,11 +257,12 @@ jobs:
           integrity_hash: ${{ inputs.source_code_integrity_hash }}
           artifact_name: ${{ inputs.source_code_artifact_name }}
 
-      - name: Download CDK layer artifact
+      - name: Download CDK layer artifacts
         uses: actions/download-artifact@eaceaf801fd36c7dee90939fad912460b18a1ffe # v4.1.2
         with:
-          name: cdk-layer-stack
-          path: cdk-layer-stack/
+          path: cdk-layer-stack
+          pattern: cdk-layer-stack-*  # merge all Layer artifacts created per region earlier (reusable_deploy_v2_layer_stack.yml; step "Save Layer ARN artifact")
+          merge-multiple: true
       - name: Replace layer versions in documentation
         run: |
           ls -la cdk-layer-stack/

.github/workflows/reusable_deploy_v2_layer_stack.yml

@@ -193,16 +193,15 @@ jobs:
         run: |
           mkdir cdk-layer-stack
           jq -r -c '.LayerV2Stack.LatestLayerArn' cdk-outputs.json > cdk-layer-stack/${{ matrix.region }}-layer-version.txt
-          jq -r -c '.LayerV2Stack.LatestLayerArm64Arn' cdk-outputs.json >> cdk-layer-stack/${{ matrix.region }}-layer-version.txt
+          jq -r -c '.LayerV2Stack.LatestLayerArm64Arn' cdk-outputs.json > cdk-layer-stack/${{ matrix.region }}-layer-version.txt
           cat cdk-layer-stack/${{ matrix.region }}-layer-version.txt
       - name: Save Layer ARN artifact
         if: ${{ inputs.stage == 'PROD' }}
         uses: actions/upload-artifact@5d5d22a31266ced268874388b861e4b58bb5c2f3 # v4.3.1
         with:
-          name: cdk-layer-stack
+          name: cdk-layer-stack-${{ matrix.region }}
           path: ./layer/cdk-layer-stack/* # NOTE: upload-artifact does not inherit working-directory setting.
           if-no-files-found: error
           retention-days: 1
-          overwrite: true
       - name: CDK Deploy Canary
         run: npx cdk deploy --app cdk.out --context region=${{ matrix.region }} --parameters DeployStage="${{ inputs.stage }}" --parameters HasARM64Support=${{ matrix.has_arm64_support }} 'CanaryV2Stack' --require-approval never --verbose