chore(deps): Update dependency digitalocean/do-agent to v3.18.8 (#25)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

roles/do/defaults/main.yml

@@ -5,7 +5,7 @@
 # Package-Konfiguration
 do_package_name: "do-agent"
 # renovate: datasource=github-releases depName=digitalocean/do-agent
-do_version: "3.18.7"
+do_version: "3.18.8"
 
 # Service-Konfiguration
 do_health_check_enabled: true