Fix comma splice

src/vendor/core/invariant.js

@@ -30,7 +30,7 @@
 function invariant(condition) {
   if (!condition) {
     var error = new Error(
-      'Minified exception occured, use the non-minified dev environment for ' +
+      'Minified exception occured; use the non-minified dev environment for ' +
       'the full error message and additional helpful warnings.'
     );
     error.framesToPop = 1;