Bump github.com/docker/docker in /testbed

Bumps [github.com/docker/docker](https://github.com/docker/docker) from 28.2.2+incompatible to 28.3.3+incompatible.
- [Release notes](https://github.com/docker/docker/releases)
- [Commits](moby/moby@v28.2.2...v28.3.3)

---
updated-dependencies:
- dependency-name: github.com/docker/docker
  dependency-version: 28.3.3+incompatible
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

testbed/go.mod

@@ -179,7 +179,7 @@ require (
 	github.com/dennwc/varint v1.0.0 // indirect
 	github.com/digitalocean/godo v1.152.0 // indirect
 	github.com/distribution/reference v0.6.0 // indirect
-	github.com/docker/docker v28.2.2+incompatible // indirect
+	github.com/docker/docker v28.3.3+incompatible // indirect
 	github.com/docker/go-connections v0.5.0 // indirect
 	github.com/docker/go-units v0.5.0 // indirect
 	github.com/dustin/go-humanize v1.0.1 // indirect

testbed/go.sum

@@ -443,8 +443,8 @@ github.com/distribution/reference v0.6.0 h1:0IXCQ5g4/QMHHkarYzh5l+u8T3t73zM5Qvfr
 github.com/distribution/reference v0.6.0/go.mod h1:BbU0aIcezP1/5jX/8MP0YiH4SdvB5Y4f/wlDRiLyi3E=
 github.com/dnaeon/go-vcr v1.2.0 h1:zHCHvJYTMh1N7xnV7zf1m1GPBF9Ad0Jk/whtQ1663qI=
 github.com/dnaeon/go-vcr v1.2.0/go.mod h1:R4UdLID7HZT3taECzJs4YgbbH6PIGXB6W/sc5OLb6RQ=
-github.com/docker/docker v28.2.2+incompatible h1:CjwRSksz8Yo4+RmQ339Dp/D2tGO5JxwYeqtMOEe0LDw=
-github.com/docker/docker v28.2.2+incompatible/go.mod h1:eEKB0N0r5NX/I1kEveEz05bcu8tLC/8azJZsviup8Sk=
+github.com/docker/docker v28.3.3+incompatible h1:Dypm25kh4rmk49v1eiVbsAtpAsYURjYkaKubwuBdxEI=
+github.com/docker/docker v28.3.3+incompatible/go.mod h1:eEKB0N0r5NX/I1kEveEz05bcu8tLC/8azJZsviup8Sk=
 github.com/docker/go-connections v0.5.0 h1:USnMq7hx7gwdVZq1L49hLXaFtUdTADjXGp+uj1Br63c=
 github.com/docker/go-connections v0.5.0/go.mod h1:ov60Kzw0kKElRwhNs9UlUHAE/F9Fe6GLaXnqyDdmEXc=
 github.com/docker/go-units v0.5.0 h1:69rxXcBk27SvSaaxTtLh/8llcHD8vYHT7WSdRZ/jvr4=