refactor: update PR comments instead of creating new ones

Author: xnoto

.github/workflows/opentofu.yml

@@ -62,25 +62,27 @@ jobs:
           tail -n 1000 plan-filtered.txt > plan-filtered-truncated.txt
           mv plan-filtered-truncated.txt plan-filtered.txt
 
-      - name: Comment PR with Plan
-        uses: actions/github-script@v7
+      - name: Find existing comment
+        uses: peter-evans/find-comment@v3
+        id: fc
         with:
-          github-token: ${{ secrets.GITHUB_TOKEN }}
-          script: |
-            const fs = require('fs');
-            const planOutput = fs.readFileSync('plan-filtered.txt', 'utf8');
+          issue-number: ${{ github.event.pull_request.number }}
+          comment-author: 'github-actions[bot]'
+          body-includes: '<!-- opentofu-plan -->'
 
-            const output = `#### OpenTofu Plan
-            \`\`\`
-            ${planOutput}
-            \`\`\`
-            `;
-            github.rest.issues.createComment({
-              issue_number: context.issue.number,
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-              body: output
-            });
+      - name: Comment PR with Plan
+        uses: peter-evans/create-or-update-comment@v4
+        with:
+          comment-id: ${{ steps.fc.outputs.comment-id }}
+          issue-number: ${{ github.event.pull_request.number }}
+          body-path: plan-filtered.txt
+          body-prefix: |
+            <!-- opentofu-plan -->
+            #### OpenTofu Plan
+            ```
+          body-suffix: |
+            ```
+          edit-mode: replace
 
   apply:
     name: OpenTofu Apply