enhance(yaml): allow for users to parse pipelines using old library

[ecrupper]

Background

It is imperative that the platform moves away from the buildkite YAML library, as it is archived.

This has been attempted and reverted a couple times:

(2024, go-yaml v3) go-vela/types#386 —> go-vela/types#392

(2020, goccy) go-vela/types#118 —> go-vela/types#144

This PR ensures that we will not have to revert this important change, as it will allow for users to immediately set

version: "legacy"

At the top level of their pipeline file (or template file) if they are encountering unexpected YAML issues.

This will also allow for troubleshooting / triaging for the Vela admins to cover all of our bases when shifting to this new library while having low impact.

The goal is to revert this change in a later release so that the entire platform uses only one YAML parser throughout the code base.

What's in the PR

• new packages compiler/types/yaml/yaml and compiler/types/yaml/buildkite in place of the single compiler/types/yaml
• all the buildkite YAML types have a ToYAML() method that will convert to the go-yaml version. Once the pipelines have been unmarshaled, these two objects should be identical sans their type.
• an internal/yaml.go file that grabs the version from the pipeline file and verifies the library we should use.

[codecov]

Codecov Report

Attention: Patch coverage is 72.95308% with 294 lines in your changes missing coverage. Please review.

Project coverage is 57.37%. Comparing base (9a4003b) to head (23205cd).

Files with missing lines	Patch %	Lines
compiler/types/yaml/buildkite/secret.go	72.72%	49 Missing and 2 partials ⚠️
compiler/types/yaml/buildkite/template.go	43.75%	36 Missing ⚠️
compiler/types/yaml/buildkite/step.go	65.68%	34 Missing and 1 partial ⚠️
compiler/types/yaml/buildkite/service.go	65.90%	28 Missing and 2 partials ⚠️
compiler/types/yaml/buildkite/ruleset.go	81.81%	28 Missing ⚠️
compiler/types/yaml/buildkite/stage.go	19.23%	21 Missing ⚠️
compiler/types/yaml/buildkite/metadata.go	66.10%	20 Missing ⚠️
compiler/types/yaml/buildkite/ulimit.go	80.61%	19 Missing ⚠️
compiler/types/yaml/buildkite/volume.go	79.78%	19 Missing ⚠️
compiler/types/yaml/buildkite/build.go	76.62%	16 Missing and 2 partials ⚠️
... and 3 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1220      +/-   ##
==========================================
+ Coverage   56.87%   57.37%   +0.49%     
==========================================
  Files         599      611      +12     
  Lines       32869    33936    +1067     
==========================================
+ Hits        18695    19471     +776     
- Misses      13538    13819     +281     
- Partials      636      646      +10     

Files with missing lines	Coverage Δ
api/pipeline/template.go	0.00% <ø> (ø)
api/types/string.go	80.64% <ø> (ø)
compiler/native/clone.go	100.00% <ø> (ø)
compiler/native/compile.go	71.39% <ø> (+0.73%)	⬆️
compiler/native/environment.go	86.75% <ø> (ø)
compiler/native/expand.go	69.20% <ø> (ø)
compiler/native/initialize.go	100.00% <ø> (ø)
compiler/native/parse.go	85.00% <100.00%> (-0.37%)	⬇️
compiler/native/script.go	95.23% <ø> (ø)
compiler/native/substitute.go	70.00% <ø> (ø)
... and 29 more