update toolchain for outdated job

Author: KodrAus

.github/workflows/outdated.yml

@@ -13,6 +13,9 @@ jobs:
     - name: Checkout repository
       uses: actions/checkout@8e5e7e5ab8b370d6c329ec480221332ada57f0ab
 
+    - name: Install Rust Toolchain
+      run: rustup update stable
+
     - name: Install cargo-outdated
       run: cargo install cargo-outdated