Fix revive-fixtures build script (#8980)

The .polkavm files are not recompiled when deleting
`target/pallet-revive-fixtures`. I assume that CI is not caching that
folder or the .polkavm file extension. This leads to the
`include_bytes!` macro to not finding these files.

Tested it here polkadot-fellows/runtimes#785

---------

Signed-off-by: Oliver Tale-Yazdi <[email protected]>
Co-authored-by: Alexander Theißen <[email protected]>

Author: ggwpez

prdoc/pr_8980.prdoc

@@ -0,0 +1,8 @@
+title: Fix revive-fixtures build script
+doc:
+- audience: Runtime Dev
+  description: |-
+    Fix compilation issue with pallet-revive-fixtures build.rs script.
+crates:
+- name: pallet-revive-fixtures
+  bump: patch

substrate/frame/revive/fixtures/build.rs

@@ -294,6 +294,7 @@ pub fn main() -> Result<()> {
 	println!("cargo::rerun-if-env-changed={OVERRIDE_RUSTUP_TOOLCHAIN_ENV_VAR}");
 	println!("cargo::rerun-if-env-changed={OVERRIDE_STRIP_ENV_VAR}");
 	println!("cargo::rerun-if-env-changed={OVERRIDE_OPTIMIZE_ENV_VAR}");
+	println!("cargo::rerun-if-changed={}", out_dir.display());
 
 	// the fixtures have a dependency on the uapi crate
 	println!("cargo::rerun-if-changed={}", fixtures_dir.display());