:gear: even more judicious drone build instructions

.drone.yml

 
 # push_deploy_key: id_rsa from DRONE host machine
 
-################
-# Build & Test #
-################
-
+##############
+# Test Theme #
+##############
 kind: pipeline
 name: run_tests
 
           - name: node_cache
             path: /drone/src/vue-theme/node_modules
 
+volumes:
+    - name: node_cache
+      host:
+          path: /tmp/cache/drone/node_modules
+    - name: build
+      host:
+          path: /tmp/cache/drone/build
+---
+#############
+# Run Build #
+#############
+kind: pipeline
+name: run_build
+depends_on:
+    # Must run after the first pipeline
+    - run_tests
+trigger:
+    status:
+        # Only runs if the first pipeline was fully successful
+        - success
+        # Only runs on the master branch
+    branch:
+        - dev
+
+steps:
     - name: build
       image: node
       commands:
 ########################
 # Deploy to Production #
 ########################
-
 kind: pipeline
 name: deploy
 depends_on:
     # Must run after the first pipeline
-    - run_tests
+    - run_build
 trigger:
     status:
         # Only runs if the first pipeline was fully successful