fix ci cache

.drone.yml

@@ -40,7 +40,7 @@ steps:
   environment:
     PRODUCER_REDIS: cache
   commands:
-  - pip3 install -r requirements.txt
+  - pip3 install --cache-dir='./.pipcache' -r requirements.txt
   - pytest integtest.py
 
 - name: build-app
@@ -59,8 +59,8 @@ steps:
 - name: make_docs
   image: python:3.8
   commands:
-  - pip3 install Sphinx sphinx_rtd_theme
-  - pip3 install -r requirements.txt
+  - pip3 install --cache-dir='./.pipcache' Sphinx sphinx_rtd_theme
+  - pip3 install --cache-dir='./.pipcache' -r requirements.txt
   - cd docs
   - make html
 
@@ -121,4 +121,5 @@ volumes:
 - name: dockersock
   temp: {}
 - name: cache
-  temp: {}
+  host:
+    path: "/tmp/cache"