chore(rootfs/Dockerfile): update golangci-lint to 1.38.0 (#273)

See https://github.com/golangci/golangci-lint/releases/tag/v1.38.0

Author: mboersma

rootfs/Dockerfile

@@ -8,7 +8,7 @@ ENV ANSIBLE_VERSION=2.10.3 \
     DOCKER_VERSION=20.10.2 \
     ETCDCTL_VERSION=v3.1.8 \
     GO_VERSION=1.15.8 \
-    GOLANGCI_LINT_VERSION=v1.31.0 \
+    GOLANGCI_LINT_VERSION=v1.38.0 \
     HELM_VERSION=3.5.0 \
     KUBECTL_VERSION=v1.16.3 \
     PACKER_VERSION=1.6.1 \