Add MSRV check to CI (#20)

* Add MSRV job to CI

* Update CI

* Add MSRV note to README

.github/workflows/rust.yml

@@ -7,16 +7,29 @@ on:
     branches: [ "main" ]
 
 env:
-  CARGO_TERM_COLOR: always
+  CARGO_INCREMENTAL: 0
+  RUSTFLAGS: "-Dwarnings"
 
 jobs:
-  build:
+  msrv:
+    runs-on: ubuntu-22.04
+
+    steps:
+      - uses: actions/checkout@v4
+      # rust-version from Cargo.toml
+      - name: Install Rust 1.65.0
+        uses: dtolnay/rust-toolchain@1.65.0
+      - name: Use predefined lockfile
+        run: mv Cargo.lock.MSRV Cargo.lock
+      - name: Build
+        run: cargo check --locked
 
+  build:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v3
-    - name: Build
-      run: cargo build --verbose
-    - name: Run tests
-      run: cargo test --verbose
+      - uses: actions/checkout@v4
+      - name: Build
+        run: cargo build
+      - name: Run tests
+        run: cargo test

Cargo.toml

@@ -2,14 +2,16 @@
 name = "ssimulacra2"
 version = "0.4.0"
 edition = "2021"
-rust-version = "1.65.0"
 description = "Rust implementation of the SSIMULACRA2 metric"
 repository = "https://github.com/rust-av/ssimulacra2"
 homepage = "https://github.com/rust-av/ssimulacra2"
 documentation = "https://docs.rs/ssimulacra2"
 exclude = ["test_data"]
 license = "BSD-2-Clause"
 
+# When changing MSRV: Also update README and .github/workflows/rust.yml
+rust-version = "1.65.0"
+
 [features]
 default = ["rayon"]
 

README.md

@@ -5,3 +5,8 @@
 [![LICENSE](https://img.shields.io/crates/l/ssimulacra2?style=for-the-badge)](https://github.com/rust-av/ssimulacra2/blob/main/LICENSE)
 
 Rust implementation of the [SSIMULACRA2 metric](https://github.com/cloudinary/ssimulacra2).
+
+## Minimum supported Rust version (MSRV)
+
+This crates requires a Rust version of 1.62.0 or higher. Increases in MSRV will result in a semver PATCH version increase.
+