Generalize the MSRV checks in the github actions workflow

.github/workflows/checks.yaml

@@ -32,7 +32,7 @@ jobs:
             os: ubuntu-latest
             features: ""
             target: "x86_64-unknown-linux-gnu"
-          - rust: "1.67.0"
+          - rust: "msrv"
             os: ubuntu-latest
             features: ""
             target: "x86_64-unknown-linux-gnu"
@@ -48,7 +48,7 @@ jobs:
             os: ubuntu-latest
             features: "--all-features"
             target: "x86_64-unknown-linux-gnu"
-          - rust: "1.67.0"
+          - rust: "msrv"
             os: ubuntu-latest
             features: "--all-features"
             target: "x86_64-unknown-linux-gnu"
@@ -65,10 +65,12 @@ jobs:
         uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
         with:
           persist-credentials: false
-      - name: Install ${{ matrix.rust }} toolchain
+      - name: Set target rust version
+        run: echo "TARGET_RUST_VERSION=$(if [ "${{matrix.rust}}" = "msrv" ]; then grep rust-version Cargo.toml | grep MSRV | cut -d'"' -f2; else echo "${{matrix.rust}}"; fi)" >> $GITHUB_ENV
+      - name: Install toolchain
         uses: dtolnay/rust-toolchain@439cf607258077187679211f12aa6f19af4a0af7
         with:
-          toolchain: ${{ matrix.rust }}
+          toolchain: "${TARGET_RUST_VERSION}"
           targets: "${{ matrix.target }}"
       - name: Install cross-compilation tools
         uses: taiki-e/setup-cross-toolchain-action@e0fdbe18d70a8bbed8a44d3319a1842949a63671

Cargo.toml

@@ -22,7 +22,7 @@ homepage = "https://github.com/pendulum-project/ntpd-rs"
 readme = "./README.md"
 description = "Full-featured implementation of NTP with NTS support"
 publish = true
-rust-version = "1.67.0" # MSRV
+rust-version = "1.67" # MSRV
 
 [workspace.metadata.release]
 sign-commit = true