docs: fix typo in README (#475)

`s/RRS/RSS/g`

Author: apricote

README.md

@@ -12,7 +12,7 @@ The library's documentation is available at [hcloud-python.readthedocs.io](https
 
 > [!IMPORTANT]
 > Make sure to follow our API changelog available at
-> [docs.hetzner.cloud/changelog](https://docs.hetzner.cloud/changelog) (or the RRS feed
+> [docs.hetzner.cloud/changelog](https://docs.hetzner.cloud/changelog) (or the RSS feed
 > available at
 > [docs.hetzner.cloud/changelog/feed.rss](https://docs.hetzner.cloud/changelog/feed.rss))
 > to be notified about additions, deprecations and removals.