chore(bousdsole): Set default merge to squash

The merge method in the boussole configuration file is now set to
"squash" by default. This ensures that all merges will use the squash
strategy unless otherwise specified.

Author: chmouel

.tekton/boussole.yaml

@@ -23,6 +23,8 @@ spec:
       value: "{{ git_auth_secret }}"
     - name: comment_sender
       value: "{{ sender }}"
+    - name: merge_method
+      value: "squash"
   #
   # Optional parameters (value is the default):
   #
@@ -44,8 +46,5 @@ spec:
   # - name: lgtm_review_event
   #   value: "APPROVE"
   #
-  # The merge method to use. Can be one of: merge, squash, rebase
-  # - name: merge_method
-  #   value: "rebase"
   pipelineRef:
     name: boussole