Add SDK version to every request

[corbadoman]

Why

To get a understanding what SDKs our customers use we need to provide the SDK version in every API request.

TODOS

• Add release version to go binary in some version constant/variable
• Add this version to every request as an additional header: X-Corbado-SDK-Version (we use an additional header because we need to preserve the User-Agent field for the real user agent of the user of our customer)
• Value: "Go SDK (release version)" so for example "Go SDK v0.3.0"

Competitors

• Stytch: https://github.com/stytchauth/stytch-go/blob/main/stytch/stytch.go#L112
• Descope: Could not find a version
• Auth0: https://github.com/auth0/go-auth0/blob/main/internal/client/client.go#L29

[corbadovych]

done in v0.4.0