Symlink bitnami kubectl location to standard path (#36)

The bitnami base image adds their location of kubectl to the PATH.

  PATH=/opt/bitnami/kubectl/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin

However this PATH location can be lost during a docker export/import
of the image, making bundling this resource difficult.

  PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin

To resolve this, we now create a symbolic link in the standard PATH location:

  /usr/local/bin/kubectl -> /opt/bitnami/kubectl/bin/kubectl

The link is preserved during export/import, so our resource scripts can
still locate kubectl even though the bitnami location is no longer on
the PATH.

See https://concourse-ci.org/concourse-worker.html#installing-or-upgrading-bundled-resource-types
Closes #35

Add kubectl 1.25 and update baselines to latest patches (#34)

Added the `1.25` baseline to list ot `kubectl` versions we ship with,
currently targeting the latest patch `1.25.2`.  The `latest` image now
also ships with `1.25`.

Also updated the current baselines to their latest patch releases:
* `1.22.12` --> `1.22.15`
* `1.23.9` --> `1.23.12`
* `1.24.3` --> `1.24.6`

Add kubectl 1.25 and update baselines to latest patches (#34)

Added the `1.25` baseline to list ot `kubectl` versions we ship with,
currently targeting the latest patch `1.25.2`.  The `latest` image now
also ships with `1.25`.

Also updated the current baselines to their latest patch releases:
* `1.22.12` --> `1.22.15`
* `1.23.9` --> `1.23.12`
* `1.24.3` --> `1.24.6`

Add kubectl 1.24 and update all baselines to latest patches

Added the `1.24` baseline to list of `kubectl` versions we ship with,
currently targeting the latest patch `1.24.1`.  The `latest` image now
also ships with `1.24`.

Also updated the current baselines to their latest patch releases:
* `1.21.11` --> `1.21.14`
* `1.22.8` --> `1.22.11`
* `1.23.5` --> `1.23.8`

Update kubectl versions and add 1.23

Updated all `kubectl` baselines to their latest patch releases.

* `1.19.15` -> `1.19.16`
* `1.20.11` -> `1.20.15`
* `1.21.5`  -> `1.21.9`
* `1.22.2`  -> `1.22.6`

And added a new release with `1.23.3`.

Build multi-arch images (#4) (#30)

Added `buildx` to all Makefile and CI builds (latest and release) so we
always build multi-arch images.

You can build and push `latest` for `linux/amd64` and `linux/arm64/v8` with:
```
make release_latest
```

Otherwise, tagging of the repo continues to trigger CI builds of the
tagged version and will now publish the image for both `linux/amd64`
and `linux/arm64/v8` architectures.

Wait for cluster conditions on PUT (#28)

New Feature!  Added support for waiting for cluster conditions after a
`put` step.  You can now (optionally) configure a `put` to wait for the
cluster to satisfy specific conditions before the step will succeed.

To enable this, simply specify an `await.timeout` param to your `put`
step:
```yaml
  params:
    await:
      timeout: 30
```

The `timeout` is measured in seconds, and must be greater than `0` to
enable waiting.

The conditions to wait for are specified in `await.conditions` as a
list:
```yaml
  params:
    await:
      timeout: 30
      conditions:
        - select(.kind == "Pod") | .status.containerStatuses[] | .ready
```
You can include any number of conditions.  In order for the wait to
succeed each expression must evaluate to at least _one_ `true` result,
and no `false` results.  Any other non `true|false` result is ignored.

If no `conditions` are specified, sensible defaults are used for the
resource types being retrieved.

If the `timeout` is exceeded before all conditions are met, the `put`
will fail.

See the updated `README` for further details.
Closes #19

Switch README.md to .adoc and add RELEASES.adoc and CONTRIBUTING.adoc (…

…#26)

Switch from markdown to asciidoc for `README`, and added _new_
`RELEASES` and `CONTRIBUTING` pages.

Add insecure_skip_tls_verify flag (#20)

Added a new optional source config option `insecure_skip_tls_verify`
that enables passing the `--insecure-skip-tls-verify` option to `kubectl`
instead of `--certificate-authority=<ca_file>`.  

When `true`, the `certificate_authority` source config is ignored and
can be omitted in the source config.  Default is `false`.

Co-authored-by: Justin Griffin <[email protected]>

Fail "check" if kubectl fails (#17)

Previously, if `kubectl` returned in error, the subshell (and pipe)
would wind up swallowing that error and returning `0` for the resource
check.

Now, any `kubectl` error is bubbled up and will cause the "check"
operation to fail.  Concourse web will then render this error in the UI
as well.

Closes #12