fix nox path

Author: bjlittle

.github/workflows/ci-docs-tests.yml

@@ -127,7 +127,7 @@ jobs:
           # Increment the build number to force a cache refresh.
           CACHE_BUILD: 0
         with:
-          path: ~/.nox
+          path: ${{ github.workspace }}/.nox
           key: dummy-${{ runner.os }}-nox-${{ env.ENV_NAME }}-py${{ matrix.python-version }}-b${{ env.CACHE_BUILD }}-${{ hashFiles(env.LOCK_FILE) }}
 
       - name: "Iris configure"