fix: support disableSslVerification when user provides https agent (watson-developer-cloud#1055)

when a user provides a custom https agent, we don't want to override the `disableSslVerification` behavior. this was happening before, but has been fixed in the core. this commit bumps the core version to include this fix

Author: dpopp07

package-lock.json

@@ -87,7 +87,7 @@
     "async": "^3.2.0",
     "camelcase": "^6.0.0",
     "extend": "~3.0.2",
-    "ibm-cloud-sdk-core": "^2.4.2",
+    "ibm-cloud-sdk-core": "2.4.4",
     "isstream": "~0.1.2",
     "websocket": "^1.0.28"
   },