[v10] Remove deprecated GenerateUserCerts HTTP endpoint (#15412)

Remove deprecated GenerateUserCerts HTTP endpoint

Co-authored-by: Brian Joerger <[email protected]>

lib/auth/apiserver.go

@@ -102,7 +102,6 @@ func NewAPIServer(config *APIConfig) (http.Handler, error) {
 
 	// Generating certificates for user and host authorities
 	srv.POST("/:version/ca/host/certs", srv.withAuth(srv.generateHostCert))
-	srv.POST("/:version/ca/user/certs", srv.withAuth(srv.generateUserCert)) // DELETE IN: 4.2.0
 
 	// Operations on users
 	srv.GET("/:version/users", srv.withAuth(srv.getUsers))
@@ -500,36 +499,6 @@ func (s *APIServer) getWebSession(auth ClientI, w http.ResponseWriter, r *http.R
 	return rawMessage(services.MarshalWebSession(sess, services.WithVersion(version)))
 }
 
-// DELETE IN: 4.2.0
-type generateUserCertReq struct {
-	Key           []byte        `json:"key"`
-	User          string        `json:"user"`
-	TTL           time.Duration `json:"ttl"`
-	Compatibility string        `json:"compatibility,omitempty"`
-}
-
-// DELETE IN: 4.2.0
-func (s *APIServer) generateUserCert(auth ClientI, w http.ResponseWriter, r *http.Request, _ httprouter.Params, version string) (interface{}, error) {
-	var req *generateUserCertReq
-	if err := httplib.ReadJSON(r, &req); err != nil {
-		return nil, trace.Wrap(err)
-	}
-	certificateFormat, err := utils.CheckCertificateFormatFlag(req.Compatibility)
-	if err != nil {
-		return nil, trace.Wrap(err)
-	}
-	certs, err := auth.GenerateUserCerts(r.Context(), proto.UserCertsRequest{
-		PublicKey: req.Key,
-		Username:  req.User,
-		Expires:   s.Now().UTC().Add(req.TTL),
-		Format:    certificateFormat,
-	})
-	if err != nil {
-		return nil, trace.Wrap(err)
-	}
-	return string(certs.SSH), nil
-}
-
 type WebSessionReq struct {
 	// User is the user name associated with the session id.
 	User string `json:"user"`