ci: add dedicated MSRV CI check (#103)

Signed-off-by: gruebel <anton.gruebel@gmail.com>

Author: gruebel

.cargo/config.toml

@@ -0,0 +1,3 @@
+[resolver]
+# https://doc.rust-lang.org/cargo/reference/config.html#resolverincompatible-rust-versions
+incompatible-rust-versions = "fallback"

.github/workflows/rust.yml

@@ -16,12 +16,11 @@ env:
   CARGO_TERM_COLOR: always
 
 jobs:
-  build:
+  test:
     runs-on: ubuntu-latest
     strategy:
       matrix:
         rust:
-          - 1.71.1 # MSRV
           - stable
           - beta
     steps:
@@ -31,10 +30,6 @@ jobs:
         with:
           toolchain: ${{ matrix.rust }}
 
-      - if: matrix.rust == '1.71.1'
-        name: Use MSRV lock file
-        run: cp Cargo.lock.msrv Cargo.lock
-
       - name: Build
         run: cargo build --verbose
 
@@ -56,3 +51,16 @@ jobs:
 
       - name: Check code quality
         run: cargo clippy -- -D warnings
+
+  msrv:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions-rust-lang/setup-rust-toolchain@v1
+        with:
+          toolchain: stable
+      - uses: taiki-e/install-action@v2
+        with:
+          tool: cargo-msrv
+      - name: Check MSRV
+        run: cargo msrv verify --output-format json