github_provider: Fix loading sub-templates

Author: mstokes-f5

lib/github_provider.js

@@ -196,7 +196,8 @@ class GitHubTemplateProvider extends BaseTemplateProvider {
                     .then(tmpldata => Template[useMst ? 'loadMst' : 'loadYaml'](tmpldata, {
                         schemaProvider,
                         dataProvider,
-                        templateProvider: this
+                        templateProvider: this,
+                        rootDir: tmplDir
                     }));
             });
     }