Add MSRV minimal versions in CI

.github/workflows/rust.yml

@@ -6,6 +6,16 @@ on:
       - main
   pull_request:
 
+env:
+  RUSTDOCFLAGS: "--default-theme ayu"
+  RUST_BACKTRACE: "1"
+  # speed up build by using clang/lld
+  CC: "clang-14"
+  CXX: "clang++-14"
+  LD: "clang-14"
+  LDFLAGS: "-fuse-ld=lld-14"
+  RUSTFLAGS: "-C linker=clang-14 -C link-arg=-fuse-ld=lld-14"
+
 jobs:
   # this checks that the readme created from rustdoc is up to date
   readmecheck:
@@ -68,6 +78,12 @@ jobs:
         os: [ubuntu-latest, windows-latest, macOS-latest]
     steps:
       - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@nightly
+        if: matrix.rust.name == 'MSRV'
+      - name: cargo -Z minimal-versions update
+        run: |
+          cargo -Z minimal-versions update
+        if: matrix.rust.name == 'MSRV'
       - uses: dtolnay/rust-toolchain@master
         with:
           toolchain: ${{matrix.rust.toolchain}}