Bump taiki-e/setup-cross-toolchain-action from 1.18.0 to 1.20.0

Bumps [taiki-e/setup-cross-toolchain-action](https://github.com/taiki-e/setup-cross-toolchain-action) from 1.18.0 to 1.20.0.
- [Release notes](https://github.com/taiki-e/setup-cross-toolchain-action/releases)
- [Changelog](https://github.com/taiki-e/setup-cross-toolchain-action/blob/main/CHANGELOG.md)
- [Commits](taiki-e/setup-cross-toolchain-action@e0fdbe1...c31d54d)

---
updated-dependencies:
- dependency-name: taiki-e/setup-cross-toolchain-action
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/checks.yaml

@@ -73,7 +73,7 @@ jobs:
           toolchain: "${TARGET_RUST_VERSION}"
           targets: "${{ matrix.target }}"
       - name: Install cross-compilation tools
-        uses: taiki-e/setup-cross-toolchain-action@e0fdbe18d70a8bbed8a44d3319a1842949a63671
+        uses: taiki-e/setup-cross-toolchain-action@c31d54d08f2ab1b6c35447b32b3f0dcb829a5b4f
         with:
           target: ${{ matrix.target }}
       - name: Install cargo-llvm-cov