change ci to avoid certain rust version

Author: colmazia

.github/workflows/ci.yaml

@@ -10,9 +10,6 @@ jobs:
 
       - name: Install Rust and rust toolchain
         uses: actions-rs/toolchain@v1
-        with:
-          toolchain: nightly
-          override: true
 
       - name: Install Wabt (wat2wasm)
         run: |