Add Gitea 1.21.4 update

src/hosting/updating-gitea.md

@@ -468,3 +468,22 @@ Updates came pretty fast, so I ran all three of these one after the other.
 	- then `q`
 	- Should be active (running).
 11. After some period of time, delete the backup file.
+
+## Updating 1.21.3 to 1.21.4
+1. `sudo systemctl stop gitea`
+2. `sudo su - git`
+3. `gitea dump -c /etc/gitea/app.ini -w /var/lib/gitea -t /tmp`
+4. `ls -l --block-size=M`
+	- `rm <old-backup-file>`
+	- `chmod a=r <new-backup-file>`
+5. `exit`
+6. `VERSION=1.21.4 && sudo wget -O gitea https://dl.gitea.io/gitea/${VERSION}/gitea-${VERSION}-linux-amd64`
+7. `sudo systemctl status gitea`
+	- then `q`
+	- Should be inactive/dead.
+8. `sudo mv gitea /usr/local/bin/gitea && sudo chmod +x /usr/local/bin/gitea`
+9. `sudo systemctl restart gitea`
+10. `sudo systemctl status gitea`
+	- then `q`
+	- Should be active (running).
+11. After some period of time, delete the backup file.