Fix compatibility with Argo Workflows 3.6

[elliotgunton]

Pull Request Checklist

• Fixes Argo Workflows 3.6 release changes #1215
• Fixes Hera does not have AW 3.6 types (pod_gc on WorkflowTemplate is not rendered correctly) #1292
• Good commit messages and/or PR title

Description of PR
Updates auto-generated models to Argo 3.6. Note there are a few changes to Hera code which are technically breaking changes (but are very simple for users to change):

• resources: Optional[ResourceRequirements] is now resources: Optional[VolumeResourceRequirements] for volumes. The attributes in the classes are the same except for claims is removed in VolumeResourceRequirements. Updated 4 examples that were using this
• cluster_name has been removed in ObjectMeta so is also removed in the Workflow class. It was never used by the Argo server (and is explicitly noted as an "ignored" field in the field description in ObjectMeta).

The rest are changes in the Argo models (i.e. in src/hera/workflows/models/io/argoproj/workflow/v1alpha1.py), that will affect users using the models directly. i.e. They'll be (relatively¹) stuck on the current Hera version until they upgrade Argo to 3.6 if they are using the following classes in Argo<3.6:

• PodGC structurally changed - see Hera does not have AW 3.6 types (pod_gc on WorkflowTemplate is not rendered correctly) #1292
• Multiple classes removed with the Artifact prefix
  • ArtifactGCSpec, ArtifactGCStatus, ArtifactNodeSpec, ArtifactResult, ArtifactResultNodeStatus
• Duration and Effect removed (now just str)
• Container imagePullPolicy is now a str not an enum (we handled either case in ContainerMixin so no change on the Hera side)

1. The workaround would be to use ModelClass.construct as seen here.

[codecov]

Codecov Report

Attention: Patch coverage is 60.00000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 86.2%. Comparing base (964f400) to head (88e7b68).

Files with missing lines	Patch %	Lines
src/hera/workflows/volume.py	50.0%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #1293     +/-   ##
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- Coverage   86.2%   86.2%   -0.1%     
=======================================
  Files         60      60             
  Lines       4091    4090      -1     
  Branches     653     653             
=======================================
- Hits        3530    3529      -1     
  Misses       391     391             
  Partials     170     170             

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