Julia not needed in workflow

.github/workflows/update_backend.yml

@@ -8,8 +8,6 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
-      - uses: julia-actions/setup-julia@v1
-      - uses: julia-actions/cache@v1
       - uses: actions/setup-python@v4
 
       - name: "Install PySR"