Pin cargo-expand to v1.0.95 (last version to support Rust v1.78.0)

Author: regexident

.github/workflows/rust.yml

@@ -40,10 +40,11 @@ jobs:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@v1
         with:
+          # update `cargo-expand` accordingly, when bumping MSRV:
           toolchain: 1.78.0
           components: rust-src
       - uses: cargo-bins/cargo-binstall@v1.12.5
-      - run: cargo binstall cargo-expand --no-confirm
+      - run: cargo binstall cargo-expand@1.0.95 --no-confirm
       - run: cargo test -- --test-threads=1
 
   fmt: