Compiler warnings while updating catkit conda environment

[asahooexo]

Here is the screenshot of the terminal. I got two warnings when I updated the environment.

[ehpor]

@RemiSoummer FYI

[raphaelpclt]

C++, seems to be an actual bug.

[ehpor]

Since properties have to be a Value object, they have to be either a float64 or a int64 type. These are the only types listed there. However, there should be a default clause that is hit when a different type somehow is passed. This is easy to implement.

In practice, the dtype validity is checked when creating the property with the stream, so it is practically impossible to have a stream-backed property with the wrong type, but strictly speaking there still should be a default return path.