Rewrite README on first run

Refs #4

Author: simonw

.github/workflows/scrape.yml

@@ -28,6 +28,8 @@ jobs:
           fi
           chmod +x scrape.sh
           echo "Created scrape.sh"
+          # And replace README.md
+          echo "# Scheduled scraper\n\nFor $REPO_DESC" >> README.md
         fi
       env:
         REPO_DESC: ${{ github.event.repository.description }}