Fix release script version calculation

[dsimansk]

Description

This should fix display version for release. IMO the build_flags.sh script was sourced too soon, before release values (especially ${TAG}) were properly populated.

/cc @rhuss

Changes

• Fix release script version calculation

Reference

Fixes #

Release Note

Fix release script version calculation

/kind bug

[codecov[bot]]

Codecov Report

Base: 79.90% // Head: 79.90% // No change to project coverage :thumbsup:

Coverage data is based on head (8dd6251) compared to base (9bbef97). Patch has no changes to coverable lines.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1737 +/- ## ======================================= Coverage 79.90% 79.90% ======================================= Files 174 174 Lines 13538 13538 ======================================= Hits 10817 10817 Misses 1982 1982 Partials 739 739 ``` Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=knative). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=knative)

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[knative-prow[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: dsimansk, rhuss

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Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/knative/client/blob/main/OWNERS)~~ [dsimansk,rhuss] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[dsimansk]

/cherry-pick release-1.7

[knative-prow-robot]

@dsimansk: new pull request created: #1741

In response to [this](https://github.com/knative/client/pull/1737#issuecomment-1268313905): >/cherry-pick release-1.7 Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes/test-infra](https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:) repository.