fix: Add undocumented github.repository_visibility option

See https://www.google.com/search?q=github+%22repository_visibility%22

Author: rasa

expr_sema.go

@@ -230,6 +230,7 @@ var BuiltinGlobalVariableTypes = map[string]ExprType{
 		"repository_owner":    StringType{},
 		"repository_owner_id": StringType{},
 		"repositoryurl":       StringType{}, // repositoryUrl
+		"repository_visibility": StringType{},
 		"retention_days":      NumberType{},
 		"run_id":              StringType{},
 		"run_number":          StringType{},