Can't add a TaxCode, URL SDK is using is incorrect

It looks like the URL is just wrong to add a Tax Code. The SDK **SHOULD** be sending the request to:
`POST /v3/company/[realmId]/taxservice/taxcode?minorversion=40`

At least, that's what the docs say.

But it appears that it is leaving the **taxcode** segment off of the url. Instead, it's posting to:
`POST /v3/company/[realmId]/taxservice?minorversion=40 `
and not finding a resource there.
We are using version 8.1 because the Serilog issues are preventing us from upgrading...but it appears that the same issue is present even in 14.x.

I have manually set the URL to the correct URL while debugging and the request works when I append "/taxcode" to the end of the URL.