Get rid of most actions-rs bits

Given that that project is unmaintained.

actions-rs/toolchain#216

Author: jonhoo

.github/workflows/nostd.yml

@@ -19,7 +19,4 @@ jobs:
       - name: rustup target add ${{ matrix.target }}
         run: rustup target add ${{ matrix.target }}
       - name: cargo check
-        uses: actions-rs/cargo@v1
-        with:
-          command: check
-          args: --target ${{ matrix.target }} --no-default-features
+        run: cargo check --target ${{ matrix.target }} --no-default-features