Lock gofumpt to v0.3.0 and run it (#18866)

We can't depend on `latest` version of gofumpt because the output will
not be stable across versions. Lock it down to the latest version
released yesterday and run it again.

modules/structs/repo.go

@@ -220,7 +220,6 @@ type GenerateRepoOption struct {
 // CreateBranchRepoOption options when creating a branch in a repository
 // swagger:model
 type CreateBranchRepoOption struct {
-
 	// Name of the branch to create
 	//
 	// required: true