BuildKit proxy CA cleanup can be disrupted by build steps

{
                    "defaultStatus": "unaffected",
                    "packageName": "github.com/moby/buildkit",
                    "platforms": [
                        "Linux"
                    ],
                    "product": "BuildKit",
                    "vendor": "moby",
                    "versions": [
                        {
                            "version": "0.31.0",
                            "status": "affected",
                            "lessThan": "0.33.1",
                            "versionType": "semver"
                        }
                    ]
                }