Fix Rustup step in CI (#115)

Seems like we finally got hit by the rustup v1.28 changes (Github action
runners likely updated between last week and now). We were previously
using [actions-rs/toolchain](https://github.com/actions-rs/toolchain)
but that has been archived for a while. Instead I've simply replaced
that action with a couple of manual `rustup` commands.

Author: jbangelo

.github/workflows/ci.yaml

@@ -70,12 +70,11 @@ jobs:
           echo $env:CMAKE_GENERATOR
 
       - name: Install rust ${{ matrix.binary_target }}
-        uses: actions-rs/toolchain@v1
-        with:
-          toolchain: ${{ matrix.toolchain }}-${{ matrix.binary_target }}
-          profile: minimal
+        run: |
+          rustup -V
+          rustup set profile minimal
+          rustup toolchain install --force-non-host ${{ matrix.toolchain }}-${{ matrix.binary_target }}
+          rustup show
 
-      - uses: actions-rs/cargo@v1
-        with:
-          command: make
-          args: --no-workspace workspace-ci-flow
+      - name: Build
+        run: cargo make --no-workspace workspace-ci-flow