[RHAIENG-1567] : Add Mergify configuration for auto-merge and conflict handling (#34)

* Add Mergify configuration for auto-merge and conflict handling

- Implemented rules for auto-merging pull requests when all conditions are met, including reviewer approvals and CI checks.
- Added actions for handling merge conflicts, including labeling and commenting to notify authors.
- Configured commit message template for merged pull requests.

This setup aims to streamline the review process and improve collaboration efficiency.

* Update Mergify configuration to enforce no failing checks for auto-merge

* Refactor Mergify configuration to remove 'needs-rebase' label actions

* Update Mergify configuration to simplify conflict handling by removing 'needs-rebase' label action

* use approved_reviews_by instead of aproved_reviews

* Fix formatting in Mergify configuration

* Update Mergify configuration

* Update Mergify configuration to correct author reference in merge conflict notification

* Update Mergify configuration to clarify the purpose of the .mergify.yml file

Author: shruthis4

.github/mergify.yml

@@ -0,0 +1,55 @@
+# .mergify.yml defines the rules for merging pull requests.
+
+pull_request_rules:
+  # PRIMARY MERGE RULE: Single comprehensive rule for auto-merge
+  - name: Auto-merge when ALL conditions met
+    conditions:
+      # ALL assigned reviewers must approve
+      - "#approved-reviews-by>=1"              # At least one approval
+      - "#changes-requested-reviews-by=0"      # No outstanding change requests
+      - "#review-requested=0"                  # No pending review requests
+      
+      # Add flexible check for all workflows:
+      - "check-failure=~^$"             # No failing checks allowed   
+
+      # PR must be ready for merge
+      - "-draft"                               # Not a draft
+      - "base=main"                           # Targeting main branch
+      - "label!=do-not-merge"                 # No blocking labels
+      - "label!=breaking-change"              # Important - requires special handling
+      
+      # Technical requirements
+      - "-conflict"                           # No merge conflicts
+
+    actions:
+      merge:
+        method: squash
+        commit_message_template: |
+          {{ title }} (#{{ number }})
+          
+          {{ body.split('Description')[0].strip() if body else '' }}
+      comment:
+        message: |
+          🎉 **Auto-merged successfully!**
+          
+          ✅ **All reviewers approved:** {{ approved_reviews_by | length }}
+          ✅ **CI checks passed:** All
+          
+          **Approved by:**
+          {% for login in approved_reviews_by %}
+          - @{{ login }}
+          {% endfor %}
+
+  - name: ping author on conflicts
+    conditions:
+      - "conflict"
+      - "-closed"
+    actions:
+      comment:
+        message: |
+          🔀 **Merge Conflict Detected**
+          
+          This pull request has merge conflicts that must be resolved before it can be merged.
+          @{{ author }} please rebase your branch.
+          
+          [Syncing a Fork Guide](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork)