chore(deps): update mccutchen/go-httpbin docker tag from 2.20.0 to v2.21.0 (docker-compose.override.dev.yml) (DefectDojo#14415)

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

Author: renovate[bot]

docker-compose.override.dev.yml

@@ -72,4 +72,4 @@ services:
         protocol: tcp
         mode: host
   "webhook.endpoint":
-    image: mccutchen/go-httpbin:2.20.0@sha256:b1620821b6ff191d911629f87a720b88df5397c2554045f1cfb1ffde17c9b898
+    image: mccutchen/go-httpbin:2.21.0@sha256:809250d14e94397f4729f617931068a9ea048231fc1a11c9e3c7cb8c28bbab8d