ci: use mold

Signed-off-by: Chris Goller <goller@gmail.com>

Author: goller

.github/workflows/main.yml

@@ -15,7 +15,7 @@ on:
 env:
   CARGO_TERM_COLOR: always
   CARGO_CACHE_VERSION: 0.8.2
-  RUSTFLAGS: "-C link-arg=-fuse-ld=lld"
+  #RUSTFLAGS: "-C link-arg=-fuse-ld=lld"
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
@@ -37,6 +37,7 @@ jobs:
           go-version: "1.21"
 
       - uses: dtolnay/rust-toolchain@stable
+      - uses: rui314/setup-mold@v1
 
       - name: Check Rust formatting
         run: cargo fmt --all -- --check