Add rust-version (#295)

- This version is different from the MSRV. It specifies the minimum
  version required to build the crate and its direct dependencies.
- Add a CI step for building the crate alone with the oldest version
  possible.
- See MSRV.md for the policy and minimal version supported by CI,
  including all example code.
- Update all actions to checkout/v3

.github/workflows/ci.yml

@@ -16,7 +16,7 @@ jobs:
           - 1.60.0
     steps:
       - name: Checkout sources
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
       - name: Update apt repos
         run: sudo apt-get -y update
       - name: Install dependencies
@@ -37,7 +37,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout sources
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
       - name: Update apt repos
         run: sudo apt-get -y update
       - name: Install dependencies
@@ -76,7 +76,7 @@ jobs:
           - 1.60.0
     steps:
       - name: Checkout sources
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
       - name: Update apt repos
         run: sudo apt-get -y update
       - name: Install dependencies
@@ -102,7 +102,7 @@ jobs:
           - minimal-web
     steps:
       - name: Checkout sources
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
       - name: Update apt repos
         run: sudo apt-get -y update
       - name: Install dependencies
@@ -118,3 +118,28 @@ jobs:
         run: cargo install --locked wasm-bindgen-cli just
       - name: Just build
         run: just build ${{ matrix.example }}
+
+  # See https://github.com/parasyte/pixels-ci-rust-version
+  rust-version:
+    name: Rust-Version
+    runs-on: ubuntu-latest
+    needs: [checks, lints]
+    strategy:
+      matrix:
+        rust:
+          - 1.56.0
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v3
+        with:
+          repository: parasyte/pixels-ci-rust-version
+      - name: Install toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: ${{ matrix.rust }}
+          override: true
+      - name: Cargo build
+        uses: actions-rs/cargo@v1
+        with:
+          command: build

Cargo.toml

@@ -4,6 +4,7 @@ description = "A tiny library providing a GPU-powered pixel frame buffer."
 version = "0.9.0"
 authors = ["Jay Oster <jay@kodewerx.org>"]
 edition = "2021"
+rust-version = "1.56.0"
 repository = "https://github.com/parasyte/pixels"
 readme = "README.md"
 keywords = ["pixels", "2D", "GPU", "framebuffer"]

MSRV.md

@@ -21,4 +21,4 @@
 
 The table above will be kept up-to-date in lock-step with CI on the main branch in GitHub. It may contain information about unreleased and yanked versions. It is the user's responsibility to consult with the [`pixels` versions page](https://crates.io/crates/pixels/versions) on `crates.io` to verify version status.
 
-The MSRV will be chosen as the minimum version of `rustc` that can successfully pass CI, including documentation, lints, and all examples. For this reason, the minimum version _supported_ may be higher than the minimum version _required_ to compile the `pixels` crate itself.
+The MSRV will be chosen as the minimum version of `rustc` that can successfully pass CI, including documentation, lints, and all examples. For this reason, the minimum version _supported_ may be higher than the minimum version _required_ to compile the `pixels` crate itself. See `Cargo.toml` for the minimal Rust version required to build the crate alone.