GitHub.DistributedTask.ObjectTemplating.TemplateValidationException: The template is not valid. /home/runner/work/proof-systems/proof-systems/./.github/actions/ocaml-shared/action.yml (Line: 20, Col: 7): Unexpected value 'shell'
at GitHub.DistributedTask.ObjectTemplating.TemplateValidationErrors.Check()
at GitHub.Runner.Worker.ActionManifestManager.ConvertRuns(IExecutionContext executionContext, TemplateContext templateContext, TemplateToken inputsToken, String fileRelativePath, MappingToken outputs)
at GitHub.Runner.Worker.ActionManifestManager.Load(IExecutionContext executionContext, String manifestFile)