chore(deps): update dependency mocha to v7 (#384)

Author: renovate-bot

dlp/package.json

@@ -22,7 +22,7 @@
   },
   "devDependencies": {
     "chai": "^4.2.0",
-    "mocha": "^6.0.0",
+    "mocha": "^7.0.0",
     "pixelmatch": "^5.0.0",
     "pngjs": "^3.3.3",
     "uuid": "^3.3.2"