ci: preview of docs on swarm (#82)

Author: AuHau

.github/workflows/check.yaml

@@ -63,3 +63,9 @@ jobs:
           mkdir /tmp/link-checker
           npx link-checker --url-ignore localhost --allow-hash-href --mkdocs --http-cache /tmp/link-checker --http-always-get --http-timeout 10000 --http-redirects 5 ./build
 
+      - name: Create preview
+        uses: ethersphere/swarm-preview-action@master
+        with:
+          bee-url: https://bee-9.gateway.ethswarm.org
+          postage-batch-id: '0000000000000000000000000000000000000000000000000000000000000000'
+          token: ${{ secrets.REPO_GHA_PAT }}