Add range checking for endpoints

This could fail when endpoints are removed during a scale down
operation.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <[email protected]>

Move to Go Client 1.17 for Kubernetes

As per change made to openfaas-operator, this bumps up the Go
client for Kubernetes to 1.17.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <[email protected]>

Update Travis runtime version

The Travis runtime version has been updated to match the version
of Go in the Dockerfile (1.13)

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <[email protected]>

Update faas-provider to 0.14.0

**What**
- Update the version of faas-provider
- Update the info handler to use the renamed `InfoResponse` struct and
  add a basic test for the handler

Signed-off-by: Lucas Roesler <[email protected]>

Change namespaces handler status code

Changing namespaces handler status code to return
200 when requested instead of 202

Signed-off-by: Martin Dekov <[email protected]>

Move proxy to k8s package

This commit moves the proxy to the k8s package so that it can be
shared with the openfaas-operator.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <[email protected]>

Move LogRequestor into k8s package

This allows the code to be vendored into the openfaas-operator.

Tested with go build.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <[email protected]>

Improve secret update error log message

Signed-off-by: Lucas Roesler <[email protected]>

Load env process value into function status

**What**
- Copies the `readFunction` method as `AsFunctionStatus` in the k8s package
  for loading a function Deployment into a FunctionStatus struct. This
  includes new tests for the method

Signed-off-by: Lucas Roesler <[email protected]>

Fix issues with namespace usage

The update handler was trying to read the namespace from a
query-string, but clients pass this in the request body. The
handler was changed to match the approach of the create handler.

Tested e2e with Kubernetes 1.14.1

Additionally the delete handler was writing HTTP headers more than
once in some conditions. This has also been updated.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <[email protected]>