Tutorial on website out of date

The tutorial on the website here is out of date and actually has several compiler errors:

https://olingo.apache.org/doc/odata4/tutorials/read/tutorial_read.html

1. The call to `serializedContent.getContent()` is redundant due to the earlier call to `serializerResult.getContent()`.
2. The `entityCollection` variable is not defined and should be `entitySet`.

I checked out the code to try and submit a patch, but the samples have correct compiling code. First time reporting a bug so not sure how to go about submitting a fix to site.