feat: add slog logging (#432)

* feat(op): user slog for logging

integrate with golang.org/x/exp/slog for logging.
provide a middleware for request scoped logging.

BREAKING CHANGES:

1. OpenIDProvider and sub-interfaces get a Logger()
method to return the configured logger;
2. AuthRequestError now takes the complete Authorizer,
instead of only the encoder. So that it may use its Logger() method.
3. RequestError now takes a Logger as argument.

* use zitadel/logging

* finish op and testing
without middleware for now

* minimum go version 1.19

* update go mod

* log value testing only on go 1.20 or later

* finish the RP and example

* ping logging release

pkg/op/auth_request_test.go

@@ -18,6 +18,7 @@ import (
 	"github.com/zitadel/oidc/v3/pkg/op"
 	"github.com/zitadel/oidc/v3/pkg/op/mock"
 	"github.com/zitadel/schema"
+	"golang.org/x/exp/slog"
 )
 
 func TestAuthorize(t *testing.T) {
@@ -38,7 +39,7 @@ func TestAuthorize(t *testing.T) {
 
 			expect := authorizer.EXPECT()
 			expect.Decoder().Return(schema.NewDecoder())
-			expect.Encoder().Return(schema.NewEncoder())
+			expect.Logger().Return(slog.Default())
 
 			if tt.expect != nil {
 				tt.expect(expect)