fix "exports read only" error

Author: v-rudkovskiy

.babelrc

@@ -22,6 +22,12 @@
                 "legacy": true
             }
         ],
+        [
+            "@babel/plugin-transform-modules-commonjs",
+            {
+                "allowTopLevelThis": true
+            }
+        ],
         "@babel/plugin-proposal-function-sent",
         "@babel/plugin-proposal-export-namespace-from",
         "@babel/plugin-proposal-numeric-separator",

dist/netlicensing-client.js

@@ -70,6 +70,7 @@
         "@babel/plugin-proposal-throw-expressions": "^7.0.0",
         "@babel/plugin-syntax-dynamic-import": "^7.0.0",
         "@babel/plugin-syntax-import-meta": "^7.0.0",
+        "@babel/plugin-transform-modules-commonjs": "^7.2.0",
         "@babel/plugin-transform-runtime": "^7.1.0",
         "@babel/preset-env": "^7.1.6",
         "@babel/runtime": "^7.1.5",