update codepipeline config to run in queue mode and added finally for cleanup in case of failure

Author: Taniya Mathur

scripts/sdlc/cfn/codepipeline-s3.yml

@@ -155,8 +155,7 @@ Resources:
                 - export IDP_CFN_PREFIX=$(make cfn-prefix) || { echo "CFN prefix generation failed"; exit 1; }
                 - make install -e IDP_CFN_PREFIX=$IDP_CFN_PREFIX
                 - make smoketest -e IDP_CFN_PREFIX=$IDP_CFN_PREFIX
-            post_build:
-              commands:
+              finally:
                 - echo "Running cleanup regardless of build result..."
                 - make uninstall -e IDP_CFN_PREFIX=$IDP_CFN_PREFIX || echo "Cleanup failed but continuing"
 
@@ -165,6 +164,7 @@ Resources:
     Properties:
       Name: !Ref PipelineName
       RoleArn: !GetAtt CodePipelineRole.Arn
+      ExecutionMode: QUEUED
       ArtifactStore:
         Type: S3
         Location: !Ref ArtifactBucket