chore(IntersectionObserverPolyfill): Update version to 0.4.3

Author: jesusbotella

package.json

@@ -48,7 +48,7 @@
     "camelcase": "^4.0.0",
     "core-js": "^2.4.1",
     "glob": "^7.1.1",
-    "intersection-observer": "^0.4.1",
+    "intersection-observer": "^0.4.3",
     "rimraf": "^2.6.1",
     "rollup": "^0.42.0",
     "rollup-plugin-commonjs": "^8.0.2",