message: feat(plugins/pagerduty): add package
diff: "@backstage/catalog-model": "^1.0.3",
  "@backstage/core-components": "^0.9.5",
  "@backstage/core-plugin-api": "^1.0.3",
  + "@backstage/errors": "^1.0.0",
  "@backstage/plugin-catalog-react": "^1.1.1",
  "@backstage/theme": "^0.2.15",
  "@material-ui/core": "^4.12.2",
  