Support triggers in CodePipeline

[gautam-nutalapati]

CodePipeline recently introduced support for triggers and execution modes: codepipeline-trigger-filters-execution-modes

codepipeline created via copilot today is triggered for any file change in repository.
Triggers gives us bit more control over when the build triggers. One of the feature we are interested in is the ability to ignore build when specific files change.

Please support triggers in codepipeline.
As v2 pipeline cost is based on action executions, it would be good to still let users create v1 pipelines if they want to.

p.s. Copilot YAML Patch Overrides can be used to add the triggers for now.