added stable toolchain to rust-toolchain usage

Author: millsks

.github/workflows/ci.yml

@@ -19,6 +19,8 @@ jobs:
 
       - name: rustup toolchain install
         uses: dtolnay/rust-toolchain@v1
+        with:
+          toolchain: stable
 
       - name: Test all Rust projects
         run: |
@@ -33,6 +35,8 @@ jobs:
 
       - name: rustup toolchain install
         uses: dtolnay/rust-toolchain@v1
+        with:
+          toolchain: stable
 
       - name: Build all Rust projects
         run: |