add missing Pkg import

Author: njericha

.github/workflows/benchmark.yml

@@ -30,6 +30,7 @@ jobs:
       - name: Install dependencies
         run: |
           julia --project=benchmark -e '
+            import Pkg;
             Pkg.develop(PackageSpec(path=pwd()));
             Pkg.instantiate()'
       - name: Run benchmark # import Pkg; Pkg.add("BenchmarkTools") # Pkg.develop(PackageSpec(path=pwd()))