insecure registry regression ?

skaffold doesn't seem to take into account the insecure registry in its latest version, is it a regression or something misconfigured?

```yaml
apiVersion: skaffold/v2beta1
kind: Config
build:
insecureRegistries:
- nexus.foo.net
tagPolicy:
sha256: {}
artifacts:
- context: .
image: go-hello-world
local:
push: true
deploy:
kubectl:
manifests:
- kubernetes-manifests/**

```

```
skaffold run -v debug --filename skaffold.yaml --default-repo nexus.foo.net/foo --insecure-registry nexus.foo.net
INFO[0000] Skaffold &{Version:v1.6.0-docs ConfigVersion:skaffold/v2beta1 GitVersion: GitCommit:b74e2f94f628b16a866abddc2ba8f05ce0bf956c GitTreeState:clean BuildDate:2020-03-25T00:09:12Z GoVersion:go1.14 Compiler:gc Platform:linux/amd64}
DEBU[0000] found config for context "minikube"
DEBU[0000] validating yamltags of struct SkaffoldConfig
DEBU[0000] validating yamltags of struct Metadata
DEBU[0000] validating yamltags of struct Pipeline
DEBU[0000] validating yamltags of struct BuildConfig
DEBU[0000] validating yamltags of struct Artifact
DEBU[0000] validating yamltags of struct ArtifactType
DEBU[0000] validating yamltags of struct DockerArtifact
DEBU[0000] validating yamltags of struct TagPolicy
DEBU[0000] validating yamltags of struct ShaTagger
DEBU[0000] validating yamltags of struct BuildType
DEBU[0000] validating yamltags of struct LocalBuild
DEBU[0000] validating yamltags of struct DeployConfig
DEBU[0000] validating yamltags of struct DeployType
DEBU[0000] validating yamltags of struct KubectlDeploy
DEBU[0000] validating yamltags of struct KubectlFlags
INFO[0000] Using kubectl context: minikube
DEBU[0000] Using builder: local
DEBU[0000] Running command: [minikube docker-env --shell none]
DEBU[0000] Command output: [DOCKER_TLS_VERIFY=1
DOCKER_HOST=tcp://192.168.99.102:2376
DOCKER_CERT_PATH=/home/foo/.minikube/certs
MINIKUBE_ACTIVE_DOCKERD=minikube
]
DEBU[0000] setting Docker user agent to skaffold-v1.6.0-docs
Generating tags...
- go-hello-world -> nexus.foo.net/foo/go-hello-world:latest
INFO[0000] Tags generated in 64.344µs
Checking cache...
DEBU[0000] Found dependencies for dockerfile: [{go.mod /src/hello-world true} {go.sum /src/hello-world true} {. /src/hello-world true}]
- go-hello-world: Not found. Building
INFO[0000] Cache check complete in 1.802348ms
Found [minikube] context, using local docker daemon.
Building [go-hello-world]...
DEBU[0000] Running command: [docker build . --file /home/foo/kubernetes/golang/go-hello-world/Dockerfile -t nexus.foo.net/foo/go-hello-world:latest]
Sending build context to Docker daemon 60.42kB
Step 1/7 : FROM golang:1.14
---> 374d57ff6662
Step 2/7 : WORKDIR /src/hello-world
---> Using cache
---> 6bf66efe1427
Step 3/7 : COPY go.mod go.sum ./
---> Using cache
---> 7ca0b4bcc8f9
Step 4/7 : RUN go mod download
---> Using cache
---> 393f43ee8bd8
Step 5/7 : COPY . ./
---> Using cache
---> fd357c8a75d7
Step 6/7 : RUN go build -o /app -v ./cmd/hello-world
---> Using cache
---> af198b2dadf5
Step 7/7 : ENTRYPOINT ["/app"]
---> Using cache
---> c52e6c26b703
Successfully built c52e6c26b703
Successfully tagged nexus.foo.net/foo/go-hello-world:latest
The push refers to repository [nexus.foo.net/foo/go-hello-world]
FATA[0001] failed to build: build failed: building [go-hello-world]: build artifact: Get https://nexus.foo.net/v2/: dial tcp 10.196.80.185:443: connect: connection refused

```