added OAuth2 displayName and pkce options

tools/auth/apple.go

@@ -36,10 +36,12 @@ type Apple struct {
 func NewAppleProvider() *Apple {
 	return &Apple{
 		baseProvider: &baseProvider{
-			scopes:   nil, // custom scopes are currently not supported since they require a POST redirect
-			ctx:      context.Background(),
-			authUrl:  "https://appleid.apple.com/auth/authorize",
-			tokenUrl: "https://appleid.apple.com/auth/token",
+			ctx:         context.Background(),
+			displayName: "Apple",
+			pkce:        true,
+			scopes:      nil, // custom scopes are currently not supported since they require a POST redirect
+			authUrl:     "https://appleid.apple.com/auth/authorize",
+			tokenUrl:    "https://appleid.apple.com/auth/token",
 		},
 		jwksUrl: "https://appleid.apple.com/auth/keys",
 	}