[BUG] Updates Kibana install doc (#1173)

Resolves #1172.

Author: jmikell821

deploy-manage/deploy/self-managed/install-kibana-with-debian-package.md

@@ -48,7 +48,7 @@ You have several options for installing the {{es}} Debian package:
 2. Save the repository definition to `/etc/apt/sources.list.d/elastic-9.x.list`:
 
     ```sh
-    echo "deb [signed-by=/usr/share/keyrings/elasticsearch-keyring.gpg] https://artifacts.elastic.co/packages/8.x/apt stable main" | sudo tee /etc/apt/sources.list.d/elastic-9.x.list
+    echo "deb [signed-by=/usr/share/keyrings/elasticsearch-keyring.gpg] https://artifacts.elastic.co/packages/9.x/apt stable main" | sudo tee /etc/apt/sources.list.d/elastic-9.x.list
     ```
 
 3. Install the {{kib}} Debian package: