Refactor setter method

packages/insomnia-app/app/plugins/context/request.js

@@ -131,14 +131,15 @@ export function init(
       }
     },
 
-
-    setAuthentication(name : string, value: string) : void {
-      renderedRequest.authentication[name] = value;
+    setAuthentication(name: string, value: string): void {
+      Object.assign(renderedRequest.authentication, {
+        [name]: value,
+      });
     },
 
-    getAuthentication() : Object {
+    getAuthentication(): Object {
       return renderedRequest.authentication;
-    }
+    },
 
     // NOTE: For these to make sense, we'd need to account for cookies in the jar as well
     // addCookie (name: string, value: string): void {}