clean up dev dependencies

addons/xterm-addon-ligatures/package.json

@@ -37,21 +37,11 @@
     "font-ligatures": "^1.3.2"
   },
   "devDependencies": {
-    "@types/chai": "^4.1.3",
-    "@types/mocha": "^5.2.0",
-    "@types/node": "^8.10.10",
     "@types/sinon": "^5.0.1",
     "axios": "^0.18.0",
-    "chai": "^4.1.2",
     "coveralls": "^3.0.2",
     "mkdirp": "^0.5.1",
-    "mocha": "^5.2.0",
-    "nyc": "^12.0.2",
     "sinon": "^6.1.3",
-    "tslint": "^5.9.1",
-    "tslint-consistent-codestyle": "^1.13.0",
-    "typescript": "^2.8.3",
-    "xterm": "^3.6.0",
     "yauzl": "^2.10.0"
   },
   "peerDependencies": {