krel does not support review-update PR workflow

#### What would you like to be added:

Allow krel to update the release notes based on the updated `map.yaml` file. The changes should be pushed to the existing PR or the existing branch created during the initial run of krel.

Also, this PR editing workflow should not fetch release notes for all PRs again and should be quick to patch a release note. (Similar to git add and git push in terms of simplicity).

#### Why is this needed:

Currently, Krel does not support updating the release notes based on review comments on the release note after the draft PR has been created.

The UI requires:

`The --fix flag is available when invoking krel with the --create-draft-pr option.`

```
$ krel release-notes --create-draft-pr --fork=Vyom-Yadav --tag=v1.34.0 --list-v2 --log-level trace --fix
DEBU Setting commands globally into verbose mode
DEBU Using log level "trace" file="cmd/root.go:83"
INFO Checking if a PR can be created from Vyom-Yadav/sig-release file="github/fork.go:72"
DEBU Using authenticated GitHub client file="github/github.go:221"
DEBU Vyom-Yadav/sig-release is a fork of kubernetes/sig-release file="github/github.go:1085"
DEBU Branch release-notes-draft-v1.34.0 already exists in Vyom-Yadav/sig-release file="github/github.go:1106"
FATA while checking kubernetes/sig-release fork: a branch named release-notes-draft-v1.34.0 already exists in Vyom-Yadav/sig-release file="cmd/root.go:59"
```

See complete discussion: https://github.com/kubernetes/sig-release/pull/2809#issuecomment-3066935689 (onwards)