[App Configuration] Use the eslint plugin (#11266)

.eslintrc.json

@@ -0,0 +1,4 @@
+{
+  "plugins": ["@azure/azure-sdk"],
+  "extends": ["plugin:@azure/azure-sdk/azure-sdk-base"]
+}

sdk/appconfiguration/app-configuration/package.json

@@ -54,8 +54,8 @@
     "execute:samples": "npm run build:samples && echo Skipped.",
     "extract-api": "tsc -p . && api-extractor run --local",
     "format": "prettier --write --config ../../../.prettierrc.json --ignore-path ../../../.prettierignore \"src/**/*.ts\" \"test/**/*.ts\" \"*.{js,json}\"",
-    "lint:fix": "eslint -c ../../.eslintrc.old.json src test samples --ext .ts --fix",
-    "lint": "eslint -c ../../.eslintrc.old.json src test --ext .ts -f html -o template-lintReport.html || exit 0",
+    "lint:fix": "eslint -c ../../../.eslintrc.json src test samples --ext .ts --fix",
+    "lint": "eslint -c ../../../.eslintrc.json src test --ext .ts -f html -o template-lintReport.html || exit 0",
     "prebuild": "npm run clean",
     "pack": "npm pack 2>&1",
     "swagger": "autorest --typescript swagger/swagger.md",
@@ -89,6 +89,7 @@
   },
   "devDependencies": {
     "@azure/dev-tool": "^1.0.0",
+    "@azure/eslint-plugin-azure-sdk": "^3.0.0",
     "@azure/identity": "^1.1.0",
     "@azure/test-utils-recorder": "^1.0.0",
     "@microsoft/api-extractor": "7.7.11",
@@ -102,6 +103,8 @@
     "@types/mocha": "^7.0.2",
     "@types/node": "^8.0.0",
     "@types/sinon": "^9.0.4",
+    "@typescript-eslint/eslint-plugin": "^2.0.0",
+    "@typescript-eslint/parser": "^2.0.0",
     "assert": "^1.4.1",
     "chai": "^4.2.0",
     "dotenv": "^8.2.0",