ci: specify project_directory in fastly config

Author: pfulton

Diff for: .github/workflows/publish-site-fastly.yml

@@ -74,6 +74,7 @@ jobs:
               with:
                   fastly-api-token: ${{ secrets.FASTLY_API_KEY }}
                   github-token: ${{ secrets.GITHUB_TOKEN }}
+                  project_directory: dist
                   service_id: ZRzI0ci9myQCiR14oxEmC7
                   comment: ${{ inputs.deploy-message }}
                   alias: ${{ inputs.alias }}