cli/config/types: remove deprecated AuthConfig.Email field

Relates to [cli@27b2797], which forked this type from the Moby API, and
[cli@aab947d], which fixed the deprecation comment.

This field is no longer used since Docker 1.11 (API version 1.23) through
[moby@aee260d] and [engine-api@9a9e468], and the fix of the deprecation
comment was included in the 28.4.0 release.

This patch removes the field.

[cli@27b2797]: 27b2797
[cli@aab947d]: aab947d
[moby@aee260d]: moby/moby@aee260d
[engine-api@9a9e468]: docker-archive-public/docker.engine-api@9a9e468

Signed-off-by: Sebastiaan van Stijn <[email protected]>

Author: thaJeztah

cli/config/types/authconfig.go

@@ -6,11 +6,6 @@ type AuthConfig struct {
 	Password string `json:"password,omitempty"`
 	Auth     string `json:"auth,omitempty"`
 
-	// Email is an optional value associated with the username.
-	//
-	// Deprecated: This field is deprecated since docker 1.11 (API v1.23) and will be removed in the next release.
-	Email string `json:"email,omitempty"`
-
 	ServerAddress string `json:"serveraddress,omitempty"`
 
 	// IdentityToken is used to authenticate the user and get