Update rtd-preview.yml (#1063)

Author: egeakman

.github/workflows/rtd-preview.yml

@@ -14,6 +14,6 @@ jobs:
     steps:
       - uses: readthedocs/actions/preview@v1
         with:
-          project-slug: "ep-website-demo"
+          project-slug: "ep-website"
           single-version: "true"
           message-template: "🖼️ Preview available 🖼️ : {docs-pr-index-url}"