Fix cloudflare pages asdf workaround (#2500)

Trying to deploy with the current asdf command gives me this error:

```
23:47:45.659	Executing user command: zola build
23:47:45.899	Building site...
23:47:45.904	Error: Failed to build the site
23:47:45.904	Error: Error parsing templates from the /templates directory
23:47:45.904	Error: Reason: Io error while writing rendered value to output: NotFound
23:47:45.904	Error: Reason: No such file or directory (os error 2)
23:47:45.906	Failed: Error while executing user command. Exited with error code: 1
23:47:45.915	Failed: build command exited with code: 1
23:47:46.837	Failed: error occurred while running build command
```

Changing the command to use the latest version, 0.18.0 fixed this.

docs/content/documentation/deployment/cloudflare-pages.md

@@ -56,7 +56,7 @@ From within the workers & pages dash, do the following:
 And add an environment variable `UNSTABLE_PRE_BUILD`, with the following value and save.
 
 ```sh
-asdf plugin add zola https://github.com/salasrod/asdf-zola && asdf install zola 0.17.2 && asdf global zola 0.17.2
+asdf plugin add zola https://github.com/salasrod/asdf-zola && asdf install zola 0.18.0 && asdf global zola 0.18.0
 ```