ensure using bash shell in renderling-build-shaders action

.github/workflows/push.yaml

@@ -23,6 +23,7 @@ jobs:
           path: ~/.cache/rust-gpu
           key: 0-${{ runner.os }}
       - uses: moonrepo/setup-rust@v1
+      - shell: bash
       - run: cargo install --git https://github.com/rust-gpu/cargo-gpu cargo-gpu
       - run: rm -rf crates/renderling/src/linkage/* crates/renderling/shaders
       - run: cargo shaders