Add support for OCI charts

[goober]

Description of your changes

This pull request aims to add support for pulling helm charts from OCI registries.

In addition, the pull request also adds support for pulling charts from insecure registries by adding the option insecureSkipTLSVerify to the Release manifest

Since helm 3.8.0 needed some newer dependencies I decided to include a dependency upgrade in this PR as well. If it is preferable to have them as separate pull requests I can split them.

Open questions:

• How should we handle insecure registries?
• Should we also add support for defining the url option with oci:// prefixed protocol? And if that is the case, should we require it to define the full tar file path? Or support the url to be defined as oci://localhost:5000/myrepo/mychart:2.7.0

Fixes #75

I have:

• Read and followed Crossplane's contribution process.
• Run make reviewable to ensure this PR is ready for review.

How has this code been tested

Following manual tests have been performed:

• repository option set to a oci:// url and also tests with version option set and without version option set.
• url option set to a oci:// url with and without :<tag> suffix
• with and without hitting the cache

[turkenh]

Thanks a lot for this @goober, looking pretty good.

I would like to do some testing while reviewing this.
Could you add/extend examples under examples/sample directory

[goober]

@turkenh Regarding the examples, do you want public hosted charts from an OCI registry that can be used or just an example url?
I have not found any good publicly available charts that can be used in the examples. Internally I have used an ECR registry in AWS during my testing

[turkenh]

@turkenh Regarding the examples, do you want public hosted charts from an OCI registry that can be used or just an example url? I have not found any good publicly available charts that can be used in the examples. Internally I have used an ECR registry in AWS during my testing

Ideally yes. Isn't it possible to use dockerhub for this purpose? For example, can we push the same workpress helm chart to dockerhub (e.g. under your own account) and add it to the example?

[goober]

Ideally yes. Isn't it possible to use dockerhub for this purpose? For example, can we push the same workpress helm chart to dockerhub (e.g. under your own account) and add it to the example?

@turkenh Unfortunately it is not supported. See docker/roadmap#135
However, I have added an example for pulling from a local registry that has been setup according to the following instructions from the Helm documentation

I have also updated the PR with support for insecure repositories and registries by adding the option insecureSkipTLSVerify to the Release manifest.

[goober]

Also upgraded kubebuilder after confirmation in the following slack thread

[turkenh]

Looking great, thanks @goober!

Added two nitpicks.

[turkenh]

@goober some checks are failing, any ideas?

[goober]

@goober some checks are failing, any ideas?

@turkenh Unfortunately not. I am running make lint locally and it goes through. Same with make reviewable

[goober]

@turkenh I ran golangci-lint run locally and found some linting errors. Upgraded golangci-lint to latest version and fixed the issues. I hope it will pass the build now

[goober]

@turkenh The pull request has now been rebased after #122 and is ready for review and testing.

[hikhvar]

Hey, I like this feature! Is there an example how to pull charts from a private OCI registry? In detail: How to configure the pull secrets for that?