Don't test on MSRV, just check

.github/workflows/pipeline.yml

@@ -26,10 +26,12 @@ jobs:
       - uses: actions-rs/cargo@v1
         name: Test all features
         with:
+          # we could use `test` but `criterion` is a dev dependency,
+          # and it doesn't build with our MSRV
+          command: check
           # `cli` already enables most features, so let's add the rest,
           # except for `arbitrary`, which requires Rust-1.51
-          command: test
-          args: --workspace --features serialize,deserialize
+          args: --workspace
       - name: Check snapshots
         run: git diff --exit-code -- tests/out
   test: