small fix in .drone.yml

.drone.yml

@@ -3,15 +3,19 @@ type: docker
 name: build
 
 steps:
-  -
-    name: build-book
-    image: 'pandoc/minimal:3'
+  - name: build-book
+    image: 'pandoc/core:3'
     commands:
-      - 'find ./chapters -iname "*.md" -type f -print | sort | xargs -r docker run --rm --volume "$(pwd):/data" --user $(id -u):$(id -g) pandoc/minimal -o book.epub title.txt'
+      - 'echo "Commit $DRONE_COMMIT"'
+      - 'find ./chapters -iname "*.md" -type f -print | sort | xargs -r pandoc -o book.epub title.txt'
   - name: gitea_release
     image: plugins/gitea-release
     settings:
-      api_key: $GITEA_TOKEN
+      api_key:
+        from_secret: gitea_token
       base_url: https://git.skobk.in
       files:
         - 'book.epub'
+    when:
+      event:
+        - tag