Include src/version in rustc.download-ci=if-changed

Author: cuviper

src/bootstrap/src/core/config/config.rs

@@ -2780,7 +2780,7 @@ impl Config {
         let has_changes = !t!(helpers::git(Some(&self.src))
             .args(["diff-index", "--quiet", &commit])
             .arg("--")
-            .args([self.src.join("compiler"), self.src.join("library")])
+            .args([self.src.join("compiler"), self.src.join("library"), self.src.join("version")])
             .as_command_mut()
             .status())
         .success();