Set and enforce an msrv of 1.64.0

This crate had an MSRV of 1.64 that was enforced in the CI; however, this was done by way of an explicit pin. Now that Rust comes with an MSRV-aware resolver, we set the `rust-version` explicitly and add a `Cargo.lock` that represents the dependencies needed to support that.

We also add a weekly CI job to ensure that the MSRV still works.

Author: akern40

.github/workflows/ci.yml

@@ -26,10 +26,6 @@ jobs:
       - uses: dtolnay/rust-toolchain@master
         with:
           toolchain: ${{ matrix.rust }}
-      - name: Pin versions for MSRV
-        if: "${{ matrix.rust == '1.64.0' }}"
-        run: |
-          cargo update -p regex --precise 1.8.4
       - name: Build
         run: cargo build --verbose
       - name: Run tests

.github/workflows/latest-deps.yml

@@ -0,0 +1,67 @@
+name: Check Latest Dependencies
+on:
+  schedule:
+    # Chosen so that it runs right before the international date line experiences the weekend.
+    # Since we're open source, that means globally we should be aware of it right when we have the most
+    # time to fix it.
+    #
+    # Sorry if this ruins your weekend, future maintainer...
+    - cron: '0 12 * * FRI'
+  workflow_dispatch: # For running manually
+  pull_request:
+    paths:
+      - '.github/workflows/latest-deps.yaml'
+
+env:
+  CARGO_TERM_COLOR: always
+  HOST: x86_64-unknown-linux-gnu
+  RUSTFLAGS: "-D warnings"
+  MSRV: 1.64.0
+
+jobs:
+  latest_deps_stable:
+    runs-on: ubuntu-latest
+    name: Check Latest Dependencies on Stable
+    steps:
+      - name: Check Out Repo
+        uses: actions/checkout@v4
+      - name: Install Rust
+        uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: stable
+      - name: Setup Mold Linker
+        uses: rui314/setup-mold@v1
+      - name: Setup Rust Cache
+        uses: Swatinem/rust-cache@v2
+      - name: Install nextest
+        uses: taiki-e/install-action@nextest
+      - name: Ensure latest dependencies
+        run: cargo update
+      - name: Run Tests
+        run: cargo nextest run
+
+  latest_deps_msrv:
+    runs-on: ubuntu-latest
+    name: Check Latest Dependencies on MSRV
+    steps:
+      - name: Check Out Repo
+        uses: actions/checkout@v4
+      - name: Install Stable Rust for Update
+        uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: stable
+      - name: Setup Mold Linker
+        uses: rui314/setup-mold@v1
+      - name: Setup Rust Cache
+        uses: Swatinem/rust-cache@v2
+      - name: Install nextest
+        uses: taiki-e/install-action@nextest
+      - name: Ensure latest dependencies
+        # The difference is here between this and `latest_deps_stable`
+        run: CARGO_RESOLVER_INCOMPATIBLE_RUST_VERSIONS="fallback" cargo update
+      - name: Install MSRV Rust for Test
+        uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: ${{ env.MSRV }}
+      - name: Run Tests
+        run: cargo nextest run

.gitignore

@@ -1,6 +1,5 @@
 /target
 **/*.rs.bk
-Cargo.lock
 
 # IDE-related
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