Update docathon-assign to 2026 label (#3836)

Update workflow to 2026 label

Author: sekyondaMeta

.github/workflows/docathon-assign.yml

@@ -28,7 +28,7 @@ jobs:
                   repo: context.repo.repo,
                   issue_number: issueNumber
                 });
-              const hasLabel = issue.labels.some(label => label.name === 'docathon-h1-2025');
+              const hasLabel = issue.labels.some(label => label.name === 'docathon-2026');
               if (hasLabel) {
                 if (issue.assignee !== null) {
                   await github.rest.issues.createComment({