Add latest agent-base as external dependency

Author: AdityaHirapara

package.json

@@ -21,7 +21,8 @@
     "https-proxy-agent": "^5.0.1",
     "is-running": "^2.1.0",
     "ps-tree": "=1.2.0",
-    "temp-fs": "^0.9.9"
+    "temp-fs": "^0.9.9",
+    "agent-base": "^6.0.2"
   },
   "devDependencies": {
     "eslint": "6.8.0",