drone.yml: /root/.pub-cache as volume

.drone.yml

@@ -6,6 +6,9 @@ name: default
 steps:
   - name: fetch
     image: cirrusci/flutter:dev
+    volumes:
+      - name: deps
+        path: /root/.pub-cache
     commands:
       - wget https://git.openprivacy.ca/openprivacy/buildfiles/raw/master/tor/tor
       - wget https://git.openprivacy.ca/openprivacy/buildfiles/raw/master/tor/torrc
@@ -27,6 +30,9 @@ steps:
 
   - name: build-linux
     image: cirrusci/flutter:dev
+    volumes:
+      - name: deps
+        path: /root/.pub-cache
     commands:
       - flutter config --enable-linux-desktop
       - apt-get update
@@ -35,6 +41,9 @@ steps:
 
   - name: build-android
     image: cirrusci/flutter:dev
+    volumes:
+      - name: deps
+        path: /root/.pub-cache
     commands:
       - flutter build appbundle
       # or build apk --split-per-abi ?
@@ -44,6 +53,9 @@ steps:
   #   requirements: Visual Studio 2019 (not to be confused with Visual Studio Code) with the “Desktop development with C++” workload installed, including all of its default components
   #- name: build-windows
   #  image: cirrusci/flutter:dev
+  #- volumes:
+  #    - name: deps
+  #      path: /root/.pub-cache
   #  commands:
   #    - flutter config --enable-windows-desktop
   #    - flutter build windows
@@ -89,6 +101,10 @@ steps:
         from_secret: gogs_account_token
     gogs_url: https://git.openprivacy.ca
 
+volumes:
+  - name: deps
+    temp: {}
+
 trigger:
   repo: flutter/flutter_app
   branch: trunk