Support for Xcode 12.0.0 has been deprecated on CircleCI. This change
updates the build configuration to use the latest stable Xcode version
available.

While testing it was found that the build steps were actually downloading an older
version of Go 1.17 and not the expected latest version. This change explicitly
sets the version of Go to be used for test builds.

There has to be a better wait to do this so we may look to replace this
config at a future time.

…by ssh.

When running a config that specifies a SSH communicator with a bastion
without any authentication option, the proposed resolution would only
include password or private key, and left agent authentication out of
the error message.

This commit adds it to the list of options to resolve it.

When a SSH bastion is used for connecting to a target, the operation is
done completely silently, making it hard to understand if it is working
as intended.

To make it easier to follow the path that the command is taking, we add
a few more INFO/DEBUG logs that parrot the actions it takes for
connecting.

* Update version of golangci-lint for Go1.18

The pinned version of golangci-lint was out of date and failing when
running with Go 1.18. This changes bumps the version to use the latest
version.

Packer recommends that we use "/" as the path separator. There is a
problem with using it on Windows because of the following behaviour:

We might pass paths with forward slashes in `StepCreateCD` struct

The string `rootFolder, err := tmp.Dir("packer_to_cdrom")` makes
rootFolder use system-based slashes, which is "\" for Windows.

This rootFolder is passed to `s.AddFile(rootFolder, toAdd)`

And a mix of two slashes ruins our replace logic while going through
the `visit` function. We end up having different slashes for `allDirs`
and `discardPath` in
`intermediaryDirs := strings.Replace(allDirs, discardPath, "", 1)`

We change our replace login to don't depend on slashes.

The tests we had didn't cover such cases as we passed all files with
paths constructed with filepath.Join(dir, fname) which returns paths
with "\\" on Windows. So we added a test case to specifically check
forward slashes.

* Provision SSHPublicKey while use custom SSH Private key

* Add tests

Bump version in preparation for the 0.3.2 release