Fix docs build in CI (#11)

* fix docs build in CI

* fix docs build in CI

Author: davorrunje

.github/workflows/docs.yml

@@ -17,7 +17,7 @@ jobs:
         python-version: '3.9'
         architecture: 'x64'
 
-    - uses: actions/cache@v1
+    - uses: actions/cache@v4
       with:
         path: |
           ~/.cache/pypoetry