Cannot release repository with build metadata

**What steps did you take:**

I tried to release a package repository with build metadata:

```
kctrl package repository release --version 2.6.0-0+git.a65d891.dirty.user.mbrauer --yes --chdir build
```

**What happened:**

`kctrl` error'd with:

```
kctrl: Error: imgpkg:
Error:
Parsing ':2.6.0-0+git.a65d891.dirty.user.mbrauer': tag can only contain the characters `abcdefghijklmnopqrstuvwxyz0123456789_-.ABCDEFGHIJKLMNOPQRSTUVWXYZ`: 2.6.0-0+git.a65d891.dirty.user.mbrauer
```

In detail:

```
❯ make repository
kctrl package repository release --version 2.6.0-0+git.a65d891.dirty.user.mbrauer --yes --chdir build

Prerequisites
1. `packages` directory containing Package and PackageMetadata files present in
the working directory.
2. Host is authorized to push images to a registry (can be set up using `docker
login`)

Basic Information
Registry URL
The bundle created needs to be pushed to an OCI registry (format:
) e.g. index.docker.io/k8slt/sample-bundlekbld ensures that all image references are resolved to an immutable reference.
Lock image references using kbld
| $ kbld -f packages --imgpkg-lock-output .imgpkg/images.yml

An imgpkg bundle consists of all required YAML configuration bundled into an OCI
image that can be pushed to an image registry and consumed by the package.
Pushing imgpkg bundle
| $ imgpkg push -b :2.6.0-0+git.a65d891.dirty.user.mbrauer -f ./bundle-:2.6.0-0+git.a65d891.dirty.user.mbrauer-3288778765 --tty=true

kctrl: Error: imgpkg:
Error:
Parsing ':2.6.0-0+git.a65d891.dirty.user.mbrauer': tag can only contain the characters `abcdefghijklmnopqrstuvwxyz0123456789_-.ABCDEFGHIJKLMNOPQRSTUVWXYZ`: 2.6.0-0+git.a65d891.dirty.user.mbrauer
```

**What did you expect:**

As per [semver#10](https://semver.org/#spec-item-10) a version can have build metadata which is delimited with a `+`. I would expect that `--version` can receive any valid semver. Unfortunately, an OCI image tag cannot contain a `+` character. I am aware that presents a challenge, but I would expect that a user of `kctrl package (repository) release` need not be concerned with that issue.

**Anything else you would like to add:**

Maybe `kctrl` could map `+` to `_` under the hood and reverse the mapping when inferring a version from a tag. In my case:
* version: `2.6.0-0+git.a65d891.dirty.user.mbrauer`
* tag: `2.6.0-0_git.a65d891.dirty.user.mbrauer`

**Environment:**

```
❯ kctrl -v
kctrl version 0.48.2

Succeeded
```

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