Set TLS version to 1.2 before making SOAP calls

[bhaarathms]

Sandbox and PROD environments only accept TLS 1.2
So we are explicitly setting TLS version to 1.2 before making SOAP calls.

[srpraveenkumar]

Looks good Bhaarath. Could you also set this in other samples in the same solution if possible?

[bhaarathms]

@srpraveenkumar added this statement in other samples too.

[JohnLBevan]

FYI: So long as the TLS protocol isn't hardcoded, you can set it via the registry, or in the AppContext.
See https://docs.microsoft.com/en-us/dotnet/framework/network-programming/tls for MS Guidelines, and https://stackoverflow.com/questions/28286086/default-securityprotocol-in-net-4-5 for various alternate approaches / discussions. Taking one of these approaches will help to take advantage of TLS1.3 once released / ensure your system' reasonably future proof.