`jx gitops upgrade` not respecting the `--dir` argument

Hello good JX community,

I'm working on a project where we use custom project templates that have some different needs:

1. Build pipeline upgrades we want to be fully consistent across all projects, and so want to use the `force-delete-replace` update strategy
2. The Helm chart we want to create from a template once but then would expect to merge changes into carefully using a less brute-force strategy

The help text for `jx gitops upgrade` suggests it should be possible to replace only my Tekton pipelines in `.lighthouse/jenkins-x` by passing the `--dir` and `--strategy` arguments, like so:

```
jx gitops upgrade —-dir .lighthouse/jenkins-x --strategy force-delete-replace
```

But in fact it tries to touch the other directories with a Kptfile in as well:

```
% jx gitops upgrade —-dir '.lighthouse/jenkins-x' --strategy force-delete-replace --verbose
upgrading local source code from the version stream using kpt...

no strategy configuration file .jx/gitops/kpt-strategy.yaml found so using default merge strategies
processing kpt directory: .lighthouse/jenkins-x wth strategy: force-delete-replace
processing kpt directory: charts/MYCHART wth strategy: force-delete-replace
error: failed to update source using kpt: failed to upgrade kpt packages in dir CHARTDIR: failed to run kpt command: failed to run '/BLAH/.jx-gitops/plugins/bin/kpt-0.37.0 pkg update charts/MYCHART@master --strategy force-delete-replace' command in directory '/BLAH', output: 'updating package charts/MYCHART to master
error: unable to read package Kptfile: charts/MYCHART Kptfile missing upstream.git.commit'
```

Running what I'd guess is the equivalent operation manually using the bundled kpt binary that `jx gitops` uses works as expected:

```
.jx-gitops/plugins/bin/kpt-0.37.0 pkg update .lighthouse/jenkins-x --strategy force-delete-replace
```

Anyone got any idea why the jx wrapper is not managing the same? I will try and look through the source code for clues but I've not worked with go before.