Run the command during deployment

Run the new command automatically during the deployment, prior to
generating the production CSS.

References #55

tools/ansible/deploy/after-update-code.yml

@@ -10,16 +10,22 @@
     chdir={{ release_theme_path }}
     creates="{{ item.creates }}"
   with_items:
+    - command: "{{ release_drush_path }} opdavies:export-body-values-for-theme-purging"
+      creates: "{{ release_theme_path }}/body-field-values.txt"
+
     - command: npm install
       creates: "{{ release_theme_path }}/node_modules"
 
     - command: npm run production
       creates: "{{ release_theme_path }}/dist"
 
-- name: Remove node_modules as they are no longer needed
+- name: Remove files that are no longer needed
   file:
-    path: "{{ release_theme_path }}/node_modules"
+    path: "{{ release_theme_path }}/{{ item }}"
     state: absent
+  with_items:
+    - body-field-values.txt
+    - node_modules
 
 - name: Generate settings.php file
   include_role: