Don't prepend marker for deserialization of root struct

[Boog900]

I didn't like the old method, this one is better

[thomaseizinger]

It seems like we'll need to bump the MSRV in CI. Can you add a changelog entry for that please?

[thomaseizinger]

I didn't like the old method, this one is better

To be honest, I am not sure I fully agree. I see it as a short-coming of the data format that the root struct does not have a marker. If you think of JSON for example, the root object is also always correctly identified. Hence, I find it quite easy to understand that we "fix" this short-coming by prepending the marker.

I am not opposed to changing it, just wondering why you think this approach is better.

[Boog900]

I agree this is a short coming of the data format but the old method felt too much like a hack for my liking. Plus doing what it was doing before causes the data to be cloned before de-serializing which will reduce performance, there probably is a way to do it without cloning but we may as well just do this.