Yarn upgrade.

.tool-versions

@@ -0,0 +1 @@
+nodejs 12.18.0

package.json

@@ -35,7 +35,6 @@
     "vuex": "^3.0.1"
   },
   "devDependencies": {
-    "karma-mocha-reporter": "^2.2.1",
     "@babel/core": "^7.7.5",
     "@babel/plugin-transform-runtime": "^7.7.6",
     "@babel/preset-env": "^7.7.6",
@@ -79,6 +78,7 @@
     "karma-coverage": "^1.1.1",
     "karma-firefox-launcher": "^1.1.0",
     "karma-mocha": "^1.2.0",
+    "karma-mocha-reporter": "^2.2.1",
     "karma-sinon-chai": "^2.0.2",
     "karma-sourcemap-loader": "^0.3.7",
     "karma-spec-reporter": "0.0.26",