created workflow to delete PR prefix after merge (#254)

.github/workflows/pr-merge.yml

@@ -0,0 +1,26 @@
+name: Delete PR prefix on merge
+run-name: Delete PR prefix on merge
+
+on:
+    pull_request:
+        types: [closed]
+
+env:
+    BUCKET_NAME: 's3://docs-staging.fused.io'
+
+jobs:
+    delete-s3-prefix:
+        if: github.event.pull_request.merged == true
+        runs-on: ubuntu-latest
+
+        steps:
+        - name: configure aws credentials
+          uses: aws-actions/configure-aws-credentials@v4
+          with:
+            role-to-assume: arn:aws:iam::926411091187:role/github_website_role
+            role-session-name: GithubFusedLabsFusedPyReleaseDocs
+            aws-region: us-west-2
+
+        - name: Delete PR prefix
+          run: |
+            aws s3 rm ${{env.BUCKET_NAME}}/pr/${{github.event.pull_request.number}} --recursive