pick up rust-toolchain.toml for CI§

.github/workflows/build_test.yml

@@ -13,23 +13,23 @@ jobs:
     name: Rust project - latest
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
-
-      # The toolchain action should definitely be run before the cache action
-      - uses: actions-rust-lang/setup-rust-toolchain@v1
-        with:
-          toolchain: stable
-          components: rustfmt, clippy
-          cache: false
-          # avoid the default "-D warnings" which thrashes cache
-          rustflags: ""
-
       - name: Install Dependencies
         run: |
           sudo apt-get update -y
           sudo apt-get upgrade -y
           sudo apt-get install libssl-dev openssl -y
 
+      - uses: actions/checkout@v4
+
+      # The toolchain action should definitely be run before the cache action
+      - uses: actions-rust-lang/setup-rust-toolchain@v1
+        with:
+          # use toolchain version from rust-toolchain.toml
+          components: rustfmt, clippy
+          cache: false
+          # avoid the default "-D warnings" which thrashes cache
+          rustflags: ""
+
       # https://github.com/actions/cache/blob/main/examples.md#rust---cargo
       - uses: actions/cache@v3
         with: