Add a slack webhook curl req for endpoint bumps

.github/workflows/bump-endpoint.yml

@@ -75,8 +75,12 @@ jobs:
           git add install-scripts/install-endpoint-mac.sh install-scripts/install-endpoint-windows.ps1
           git commit -m "Bump Endpoint to ${NEW}"
           git push origin "$BRANCH"
-          gh pr create \
+          PR_URL=$(gh pr create \
             --title "Bump Endpoint to ${NEW}" \
             --body "Automated bump of safechain-internals endpoint from \`${OLD}\` to \`${NEW}\`." \
             --head "$BRANCH" \
-            --base main
+            --base main)
+
+          curl -s -X POST "https://hooks.slack.com/triggers/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" \
+            -H "Content-Type: application/json" \
+            -d "{\"text\": \"update to ${NEW} - ${PR_URL}\"}"