Add PDBs to pre-built signed DLLs on release

[simco50]

Hi,

Given that the error results in the API are very minimal and there is little to no error message feedback, adding the PDB of the pre-built DLL to the release would be immensely useful, as this now requires compiling locally. Shipping a locally compiled binary doesn't seem like a great idea as it won't be signed, so this is not ideal.

Thanks, Simon