chore: exclude auto-generated OpenAPI file and GitHub workflows from YAML formatting (#741)

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

Author: aaronsteers

.prettierignore

@@ -1,3 +1,10 @@
 # Ignore artifacts:
 build
 coverage
+
+# Ignore auto-generated files:
+airbyte_cdk/manifest_server/openapi.yaml
+
+# Ignore GitHub workflow files:
+.github/**/*.yml
+.github/**/*.yaml