/home/runner/work/playos/playos/./.github/actions/prep-build-env/action.yml (Line: 5, Col: 5): Required property is missing: shell

GitHub.DistributedTask.ObjectTemplating.TemplateValidationException: The template is not valid. /home/runner/work/playos/playos/./.github/actions/prep-build-env/action.yml (Line: 5, Col: 5): Required property is missing: 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)

Failed to load /home/runner/work/playos/playos/./.github/actions/prep-build-env/action.yml

Error when evaluating 'strategy' for job 'integration-tests'. .github/workflows/test.yml (Line: 30, Col: 15): Error parsing fromJson,.github/workflows/test.yml (Line: 30, Col: 15): Error reading JToken from JsonReader. Path '', line 0, position 0.,.github/workflows/test.yml (Line: 30, Col: 15): Unexpected value ''