chore(deps): update dependency eslint to v9

Author: renovate[bot]

package.json

@@ -4,7 +4,7 @@
     "@sourcegraph/eslint-config": "^0.20.19",
     "@sourcegraph/prettierrc": "^3.0.3",
     "@sourcegraph/tsconfig": "^4.0.1",
-    "eslint": "^7.18.0",
+    "eslint": "^9.9.0",
     "husky": "^4.3.8",
     "prettier": "^2.2.1",
     "typescript": "^4.1.3"