added msrv ci from extendr repo

.github/workflows/msrv.yml

@@ -0,0 +1,41 @@
+name: Check MSRV
+on:
+  push:
+    branches:
+      - master
+    paths:
+      - "**.rs"
+      - "Cargo.toml"
+      - "**/Cargo.toml"
+  pull_request:
+    branches:
+      - master
+    paths:
+      - "**.rs"
+      - "Cargo.toml"
+      - "**/Cargo.toml"
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+
+jobs:
+  test-min-rust-version:
+    # PowerShell core is available on all platforms and can be used to unify scripts
+    defaults:
+      run:
+        shell: pwsh
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: baptiste0928/cargo-install@v3
+        with:
+          crate: cargo-msrv
+      - name: Verify minimum rust version
+        run: |
+          . ./ci-cargo.ps1
+          ci-cargo msrv --path extendr-api/ verify -ActionName "Verify Rust MSRV"

Cargo.toml

@@ -15,6 +15,7 @@ license = "MIT"
 links = "R"
 documentation = "https://docs.rs/libR-sys/latest/libR_sys/"
 repository = "https://github.com/extendr/libR-sys"
+rust-version = "1.67"
 
 [dependencies]