fix skeptic

serde_macros/build.rs

@@ -1,13 +1,14 @@
-#[cfg(feature = "nightly-testing")]
+#[cfg(feature = "unstable-testing")]
 mod inner {
     extern crate skeptic;
 
     pub fn main() {
+        println!("cargo:rerun-if-changed=../README.md");
         skeptic::generate_doc_tests(&["../README.md"]);
     }
 }
 
-#[cfg(not(feature = "nightly-testing"))]
+#[cfg(not(feature = "unstable-testing"))]
 mod inner {
     pub fn main() {}
 }