Fix CI error for x86_64-pc-windows-msvc

[hug-dev]

Had a weird error happening when compiling for x86_64-pc-windows-msvc:

error: reference to packed field is unaligned                                                                                                                                                                                                                                               
   --> cryptoki/src/context/general_purpose.rs:46:30                                                                                                                                                                                                                                        
    |                                                                                                                                                                                                                                                                                       
46  |                     .is_some()                                                                                                                                                                                                                                                        
    |                              ^                                                                                                                                                                                                                                                        
...                                                                                                                                                                                                                                                                                         
188 |         Function::GenerateKeyPair => check_fn!(ctx, GenerateKeyPair),                                                                                                                                                                                                                 
    |                                      ------------------------------- in this macro invocation                                                                                                                                                                                         
    |                                                                                                                                                                                                                                                                                       
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!                                                                                                                                                       
    = note: for more information, see issue #82523 <https://github.com/rust-lang/rust/issues/82523>                                                                                                                                                                                         
    = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)                                                                                                                     
    = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers)                                                           
    = note: this error originates in the macro `check_fn` (in Nightly builds, run with -Z macro-backtrace for more info)                                                                                                                                                                    
                                                                                                                                                                                                                                                                                            

This applies the tip and move things in a local variable.

[wiktor-k]

In general this looks weird but good to me 👍

In a more broader context two notes:

1. it seems CI is already configured to run with MSVC and it didn't complain :-/
2. maybe we should adjust the CI workflow yaml to use matrix builds since currently it's not easily visible if and when given target build fails.

[ionut-arm]

I'm hoping to get some time after August to improve the CI, testing, and expand support of this repo... :] but it'll have to wait