repos: add option include_all_branches to template repo request

This option, when set to true, the created repository will get files
from all the branches, not just the default branch.

See [create-a-repository-using-a-template][1] for more information.

[1]: https://docs.github.com/en/rest/reference/repos#create-a-repository-using-a-template

github/repos.go

@@ -385,7 +385,8 @@ type TemplateRepoRequest struct {
 	Owner       *string `json:"owner,omitempty"`
 	Description *string `json:"description,omitempty"`
 
-	Private *bool `json:"private,omitempty"`
+	IncludeAllBranches *bool `json:"include_all_branches,omitempty"`
+	Private            *bool `json:"private,omitempty"`
 }
 
 // CreateFromTemplate generates a repository from a template.