chore(deps): update dependency mocha to v8 (#448)

Author: renovate-bot

packages/google-cloud-monitoring/package.json

@@ -56,7 +56,7 @@
     "jsdoc-fresh": "^1.0.1",
     "jsdoc-region-tag": "^1.0.2",
     "linkinator": "^2.0.0",
-    "mocha": "^7.0.1",
+    "mocha": "^8.0.0",
     "null-loader": "^4.0.0",
     "pack-n-play": "^1.0.0-2",
     "sinon": "^9.0.1",

packages/google-cloud-monitoring/samples/package.json

@@ -19,7 +19,7 @@
   },
   "devDependencies": {
     "chai": "^4.2.0",
-    "mocha": "^7.0.0",
+    "mocha": "^8.0.0",
     "uuid": "^8.0.0"
   }
 }