feat(op): implemented support for client_credentials grant (#172)

* implemented support for client_credentials grant

* first draft

* Update pkg/op/token_client_credentials.go

Co-authored-by: Livio Amstutz <livio.a@gmail.com>

* updated placeholder interface name

* updated import paths

* ran mockgen

Co-authored-by: Livio Amstutz <livio.a@gmail.com>

pkg/op/mock/authorizer.mock.go

@@ -7,9 +7,9 @@ package mock
 import (
 	reflect "reflect"
 
+	gomock "github.com/golang/mock/gomock"
 	http "github.com/zitadel/oidc/pkg/http"
 	op "github.com/zitadel/oidc/pkg/op"
-	gomock "github.com/golang/mock/gomock"
 )
 
 // MockAuthorizer is a mock of Authorizer interface.

pkg/op/mock/client.mock.go

@@ -8,9 +8,9 @@ import (
 	reflect "reflect"
 	time "time"
 
+	gomock "github.com/golang/mock/gomock"
 	oidc "github.com/zitadel/oidc/pkg/oidc"
 	op "github.com/zitadel/oidc/pkg/op"
-	gomock "github.com/golang/mock/gomock"
 )
 
 // MockClient is a mock of Client interface.

pkg/op/mock/configuration.mock.go

@@ -7,8 +7,8 @@ package mock
 import (
 	reflect "reflect"
 
-	op "github.com/zitadel/oidc/pkg/op"
 	gomock "github.com/golang/mock/gomock"
+	op "github.com/zitadel/oidc/pkg/op"
 	language "golang.org/x/text/language"
 )
 
@@ -105,6 +105,20 @@ func (mr *MockConfigurationMockRecorder) EndSessionEndpoint() *gomock.Call {
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "EndSessionEndpoint", reflect.TypeOf((*MockConfiguration)(nil).EndSessionEndpoint))
 }
 
+// GrantTypeClientCredentialsSupported mocks base method.
+func (m *MockConfiguration) GrantTypeClientCredentialsSupported() bool {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "GrantTypeClientCredentialsSupported")
+	ret0, _ := ret[0].(bool)
+	return ret0
+}
+
+// GrantTypeClientCredentialsSupported indicates an expected call of GrantTypeClientCredentialsSupported.
+func (mr *MockConfigurationMockRecorder) GrantTypeClientCredentialsSupported() *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "GrantTypeClientCredentialsSupported", reflect.TypeOf((*MockConfiguration)(nil).GrantTypeClientCredentialsSupported))
+}
+
 // GrantTypeJWTAuthorizationSupported mocks base method.
 func (m *MockConfiguration) GrantTypeJWTAuthorizationSupported() bool {
 	m.ctrl.T.Helper()

pkg/op/mock/storage.mock.go

@@ -9,9 +9,9 @@ import (
 	reflect "reflect"
 	time "time"
 
+	gomock "github.com/golang/mock/gomock"
 	oidc "github.com/zitadel/oidc/pkg/oidc"
 	op "github.com/zitadel/oidc/pkg/op"
-	gomock "github.com/golang/mock/gomock"
 	jose "gopkg.in/square/go-jose.v2"
 )