adding workaround for compile cache failing to load with recent JAX

.github/workflows/unittest.yaml

@@ -20,6 +20,10 @@ jobs:
           pip install -U pip
           pip install .[dev]
 
+      - name: Workaround for compilation cache failure
+        run: |
+          pip install etils[epath]
+
       - name: Log installed environment
         run: |
           python3 -m pip freeze