chore(deps): update ghcr.io/open-feature/sync-testbed-unstable docker tag to v0.5.13 (open-feature#333)

Signed-off-by: Weyert de Boer <weyert@innerfuse.biz>

Author: renovate[bot]

src/OpenFeature.Contrib.Providers.Flagd/docker-compose.yaml

@@ -12,6 +12,6 @@ services:
     ports:
       - 9090:9090
   flagd-sync-unstable:
-    image: ghcr.io/open-feature/sync-testbed-unstable:v0.5.6
+    image: ghcr.io/open-feature/sync-testbed-unstable:v0.5.13
     ports:
       - 9091:9090