build for multiple platforms only in CI, add s390x

Developers should not be forced to build for all platforms by
default. We also don't want to copy-and-paste the go invocation for
each new platform.

To address both, the target platform(s) are now configurable via
BUILD_PLATFORMS and additional platforms are only enabled in the Prow
CI.

For now this serves as a test that the source actually compiles for
multiple platforms. Building images for different target platforms is a
different problem.

prow.sh: use 1.3.0 hostpath driver for testing

The final 1.3.0 release of the hostpath driver really uses the 1.3.0
driver image in its deployment, in contrast to the previous -rc
candidates which still used 1.2.0.

Change 'make test-vet' back to call 'go vet'

prow.sh: generic driver installation

prow.sh: also configure feature gates for kubelet

That this hasn't been done before is an oversight. Apparently it
hasn't been a problem because there never have been feature gates that
mattered?

This relies on a slightly different deployment script: a "deploy.sh"
must exist which knows that it has to dump a test driver configurion
into the file pointed to with CSI_PROW_TEST_DRIVER, if that env
variable is set.

That way, we no longer need to know what capabilities the installed
driver has.

fix incorrect link

Document the process for releasing a new sidecar

Update hostpath driver version to get fix for connection-timeout

Update snapshotter to version v2.0.0

Signed-off-by: Grant Griffiths <grant@portworx.com>

Fix overriding of junit results

Update prow hostpath driver version to 1.3.0-rc2

Fix version_gt to work with Kubernetes prefix

Signed-off-by: Grant Griffiths <grant@portworx.com>

Enable snapshot tests in 1.17 to be run in non-alpha jobs.

This requires adding one more parallel e2e test run with
a special focus flag because snapshot tests are still guarded
with a "[Feature:VolumeSnapshotDataSource]" tag. The setting that
skips all tests with "[Feature:.*]" has to be removed because it
overrides the focus.

We don't have serial snapshot tests yet. This needs to be modified
again if we add any in the future.

Improve README by adding an explicit Kubernetes dependency section

fix syntax for ppc64le build

Improve snapshot-controller running check and version_gt to support multiple formats 

Enable topology testing with hostpath driver

Signed-off-by: Grant Griffiths <grant@portworx.com>

Create a kind cluster with two worker nodes so that the topology feature can be tested. Test cases that test accessing volumes from multiple nodes need to be skipped

Use kind v0.6.0

kind v0.6.0 appends the kubeconfig with the default config at
~/.kube/config.

Adding build for ppc64le

Add snapshotter CRDs after cluster setup

Signed-off-by: Grant Griffiths <grant@portworx.com>

delete kind cluster after tests run