Update self-hosted changelog: v1.0.18 (#6938)

Co-authored-by: thesandlord <8902396+thesandlord@users.noreply.github.com>

Author: thesandlord

fern/products/docs/pages/self-hosted/changelog/2026-09-13.mdx

@@ -0,0 +1,7 @@
+### v1.0.18
+
+```dockerfile
+FROM fernenterprise/fern-self-hosted:1.0.18
+```
+
+Digest: `sha256:ab2bdabc9262b4587fba81d6a217ef6aeffbc481e7230d8c529528ba1943d337`