Revert "update karma and webpack-stream packages (prebid#3966)" (preb…

…id#4003)

This reverts commit 6399ab1.

package.json

@@ -58,7 +58,7 @@
     "is-docker": "^1.1.0",
     "istanbul": "^0.4.5",
     "istanbul-instrumenter-loader": "^3.0.0",
-    "karma": "^4.1.0",
+    "karma": "^3.1.3",
     "karma-babel-preprocessor": "^6.0.1",
     "karma-browserstack-launcher": "^1.3.0",
     "karma-chai": "^0.1.0",
@@ -91,7 +91,7 @@
     "webdriverio": "^4.13.2",
     "webpack": "^3.0.0",
     "webpack-bundle-analyzer": "^3.3.2",
-    "webpack-stream": "^5.2.1",
+    "webpack-stream": "^3.2.0",
     "yargs": "^1.3.1"
   },
   "dependencies": {