fix: segfault when rendering fails

Signed-off-by: Steeve Chailloux <steeve.chailloux@proton.ch>

runner/main.go

@@ -330,6 +330,7 @@
 			f, err := r.runCommand(tmpDir, name, c)
 			if err != nil {
 				errors <- err
+				return
 			}
 			results <- f.Name()
 		}(name, command)