build: specify rust stable for github actions

.github/workflows/release.yml

@@ -28,6 +28,7 @@ jobs:
         with:
           RUSTTARGET: ${{ matrix.target }}
           ARCHIVE_TYPES: ${{ matrix.archive }}
+          TOOLCHAIN_VERSION: stable
       - name: Upload artifact
         uses: actions/upload-artifact@v3
         with: