Pin mocha < 7.2.0 for NodeJS8

Author: gpotter2

package.json

@@ -44,7 +44,7 @@
   "devDependencies": {
     "@types/node": "^14.0.10",
     "chai": "^4.2.0",
-    "mocha": "^8.1.3",
+    "mocha": "^7.2.0",
     "sinon": "^9.0.2",
     "typescript": "^4.0.3"
   },