Potential fix for pull request finding

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
Signed-off-by: Nathan Randall <70299490+data-douser@users.noreply.github.com>

Author: data-douser

.github/actions/setup-codeql-environment/action.yml

@@ -463,7 +463,7 @@ runs:
 
     - name: Setup Rust toolchain
       if: inputs.install-language-runtimes == 'true' && contains(inputs.languages, 'rust')
-      uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable
+      uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # 1.88.0
       with:
         toolchain: ${{ inputs.rust-version }}
         components: rust-src