ci: use cargo-rustc to build ergo-lib as rlib

Author: SethDusek

.github/workflows/ci.yml

@@ -27,8 +27,8 @@ jobs:
       - name: Build ergo-lib
         uses: actions-rs/cargo@v1
         with:
-          command: build
-          args: --no-default-features --manifest-path ergo-lib/Cargo.toml
+          command: rustc
+          args: --no-default-features --manifest-path ergo-lib/Cargo.toml --crate-type rlib
 
   test:
     name: Tests on ${{ matrix.os }}