Migrate to maintained workflow toolchain action.

.github/workflows/ci.yml

@@ -65,11 +65,10 @@ jobs:
           sudo apt-get install -y libmysqlclient-dev libpq-dev libsqlite3-dev
 
       - name: Install Rust
-        uses: actions-rs/toolchain@v1
+        uses: dtolnay/rust-toolchain@master
+        id: toolchain
         with:
-          profile: minimal
           toolchain: ${{ matrix.platform.toolchain }}
-          override: true
           components: rust-src
 
       - name: Cache Example Workspace
@@ -77,13 +76,13 @@ jobs:
         uses: Swatinem/rust-cache@v2
         with:
           workspaces: examples
-          key: ${{ matrix.test.name }}
+          key: ${{ matrix.test.name }}-${{ steps.toolchain.outputs.cachekey }}
 
       - name: Cache Root Workspace
         if: matrix.test.name != 'Examples'
         uses: Swatinem/rust-cache@v2
         with:
-          key: ${{ matrix.test.name }}
+          key: ${{ matrix.test.name }}-${{ steps.toolchain.outputs.cachekey }}
 
       - name: Run Tests
         continue-on-error: ${{ matrix.fallible }}