cd: update drone config file to trigger pipeline on pull request

.drone.yml

@@ -1,16 +1,16 @@
 # Copyright (C) 2022 WYATT GROUP
 # Please see the AUTHORS file for details.
-# 
+#
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation, either version 3 of the License, or
 # any later version.
-# 
+#
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 # GNU General Public License for more details.
-# 
+#
 # You should have received a copy of the GNU General Public License
 # along with this program. If not, see <https://www.gnu.org/licenses/>.
 
@@ -19,18 +19,19 @@ type: docker
 name: default
 
 steps:
-- name: quality-check
-  image: git.wyatt-studio.fr/wyatt-foss/flutter-melos:2.9.0-1
-  commands:
-  - melos run quality-check
-  - melos run publish:validate
-- name: publish
-  image: git.wyatt-studio.fr/wyatt-foss/flutter-melos:2.9.0-1
-  commands:
-  - melos run publish:validate
+  - name: quality-check
+    image: git.wyatt-studio.fr/wyatt-foss/flutter-melos:2.9.0-1
+    commands:
+      - melos run quality-check
+      - melos run publish:validate
+  - name: publish
+    image: git.wyatt-studio.fr/wyatt-foss/flutter-melos:2.9.0-1
+    commands:
+      - melos run publish:validate
 
 trigger:
   branch:
-  - master
+    - master
   event:
-  - push
+    - push
+    - pull_request