chore(deps): update ghcr.io/open-feature/flagd-testbed docker tag to v0.4.8 (#570)

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

Author: renovate[bot]

.github/workflows/ci.yml

@@ -14,7 +14,7 @@ jobs:
     services:
       # flagd-testbed for flagd-provider e2e tests
       flagd:
-        image: ghcr.io/open-feature/flagd-testbed:v0.4.7
+        image: ghcr.io/open-feature/flagd-testbed:v0.4.8
         ports:
           - 8013:8013
       # sync-testbed for flagd-provider e2e tests