Merge pull request #933 from XhmikosR/deps

Update devDependencies.

Author: paulmillr

package.json

@@ -27,9 +27,9 @@
   "devDependencies": {
     "@types/node": "^12",
     "chai": "^4.2",
-    "dtslint": "0.4.1",
-    "eslint": "^6.5.1",
-    "mocha": "^6.2.1",
+    "dtslint": "0.9.9",
+    "eslint": "^6.6.0",
+    "mocha": "^6.2.2",
     "nyc": "^14.1.1",
     "rimraf": "^3.0.0",
     "sinon": "^7.5.0",