sfowl: Automated cherry pick of #94712: avoid potential secret leaking while reading .dockercfg

JobBuild
95348
10-08 05:22
3083d194
10-08 05:21
pull-kubernetes-bazel-build 1314073349558636544
pull-kubernetes-bazel-test 1314073349575413760
pull-kubernetes-dependencies 1314073349592190976
pull-kubernetes-e2e-gce 1314073349499916288
pull-kubernetes-e2e-gce-100-performance 1314073349541859328
pull-kubernetes-integration 1314073349617356800
pull-kubernetes-node-e2e 1314094428385710080 1314073349520887808
pull-kubernetes-typecheck 1314073349629939712
pull-kubernetes-verify 1314073349650911232