chore(workflows): use rustup directly to not depend on external actions (#258)

.github/workflows/check.yml

@@ -17,9 +17,10 @@ jobs:
     - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
       with:
         submodules: recursive
-    - uses: dtolnay/rust-toolchain@d0e72ca3bfdc51937a4f81431ccbed269ef9f2a2 # stable
-      with:
-        components: rustfmt
+    - run: |
+        rustup update --no-self-update stable
+        rustup default stable
+        rustup component add rustfmt
     - run: ./hack/ci/install-linux-deps.sh
     # Temporarily ignored: https://github.com/edera-dev/krata/issues/206
     - run: ./hack/build/cargo.sh fmt --all -- --check || true