Change authorization header key (#6)

* Change authorization header key

as the use of headers starting with X- has been deprecated in RFC6648.

* Update configuration.example.yaml

Co-authored-by: Sebastian Serth <MrSerth@users.noreply.github.com>

internal/api/auth/auth.go

@@ -9,7 +9,7 @@ import (
 
 var log = logging.GetLogger("api/auth")
 
-const TokenHeader = "X-Poseidon-Token"
+const TokenHeader = "Poseidon-Token"
 
 var correctAuthenticationToken []byte