Manually parse Rust toolchain spec

b/c actions-rs/toolchain doesn't support rust-toolchain.toml, see
actions-rs/toolchain#209

Author: atodorov

.github/workflows/ci.yml

@@ -21,9 +21,15 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - name: Configure rustc version
+        run: |
+          RUSTC_VERSION=$(cat rust-toolchain.toml | grep channel | tail -n1 | tr -d " " | cut -f2 -d'"')
+          echo "RUSTC_VERSION=$RUSTC_VERSION" >> "$GITHUB_ENV"
+
       - name: Install Rust toolchain
         uses: actions-rs/toolchain@v1
         with:
+          toolchain: ${{ env.RUSTC_VERSION }}
           profile: minimal
           override: true
           components: rustfmt
@@ -40,9 +46,15 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - name: Configure rustc version
+        run: |
+          RUSTC_VERSION=$(cat rust-toolchain.toml | grep channel | tail -n1 | tr -d " " | cut -f2 -d'"')
+          echo "RUSTC_VERSION=$RUSTC_VERSION" >> "$GITHUB_ENV"
+
       - name: Install Rust toolchain
         uses: actions-rs/toolchain@v1
         with:
+          toolchain: ${{ env.RUSTC_VERSION }}
           target: wasm32-unknown-unknown
           profile: minimal
           override: true
@@ -64,9 +76,15 @@ jobs:
       # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
       - uses: actions/checkout@v4
 
+      - name: Configure rustc version
+        run: |
+          RUSTC_VERSION=$(cat rust-toolchain.toml | grep channel | tail -n1 | tr -d " " | cut -f2 -d'"')
+          echo "RUSTC_VERSION=$RUSTC_VERSION" >> "$GITHUB_ENV"
+
       - name: Install Rust toolchain
         uses: actions-rs/toolchain@v1
         with:
+          toolchain: ${{ env.RUSTC_VERSION }}
           target: wasm32-unknown-unknown
           profile: minimal
           override: true