Pipelines updates: V2 pipeline and newer Linux build image

[gregbreen]

The CI/CD pipeline currently uses the STANDARD_6_0 build image, and this includes node.js 16 which is deprecated. Update to STANDARD_7_0.

Codepipeline recently announced several new features:

• https://aws.amazon.com/about-aws/whats-new/2023/10/aws-codepipeline-triggering-git-tags/
• https://aws.amazon.com/about-aws/whats-new/2023/10/aws-codepipeline-parameterized-pipelines/
• https://aws.amazon.com/about-aws/whats-new/2023/11/aws-codepipeline-pipeline-execution-source-revision-overrides/

The pipeline version should be explicitly specified in the definition, to prevent CDK warning:

[Warning at /AWSLabsCertificateRotatorPipeline/AWSLabsCertificateRotatorPipeline] V1 pipeline type is implicitly selected when `pipelineType` is not set. If you want to use V2 type, set `PipelineType.V2`. [ack: @aws-cdk/aws-codepipeline:unspecifiedPipelineType]