chore: update core to 0.19, api to rc0 (#440)

Author: dyladan

package.json

@@ -63,7 +63,7 @@
     "webpack": "4.46.0"
   },
   "dependencies": {
-    "@opentelemetry/api": "^0.18.0",
-    "@opentelemetry/core": "^0.18.0"
+    "@opentelemetry/api": "^1.0.0-rc.0",
+    "@opentelemetry/core": "^0.19.0"
   }
 }