fix(deps): update ghcr.io/containerbase/sidecar docker tag to v9.8.7 (#23744)

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

lib/config/options/index.ts

@@ -370,7 +370,7 @@ const options: RenovateOptions[] = [
     description:
       'Change this value to override the default Renovate sidecar image.',
     type: 'string',
-    default: 'ghcr.io/containerbase/sidecar:9.8.6',
+    default: 'ghcr.io/containerbase/sidecar:9.8.7',
     globalOnly: true,
   },
   {