`SciSharp.TensorFlow.Redist` had to be downgraded

https://github.com/SciSharp/TensorFlow.NET/issues/466

```
System.EntryPointNotFoundException
  HResult=0x80131523
  Message=Unable to find an entry point named 'TF_StringEncodedSize' in DLL 'tensorflow'.
  Source=<Cannot evaluate the exception source>
  StackTrace:
<Cannot evaluate the exception stack trace>
```