GH-50670: [Release][Dev] Fix only shellcheck SC2086 errors in the dev directory (#50671)

### Rationale for this change

This is the sub issue #44748.

Fix only ShellCheck SC2086 errors in the dev directory.

* SC2086: Double quote to prevent globbing and word splitting.

```
shellcheck dev/release/post-01-tag.sh

In dev/release/post-01-tag.sh line 34:
git tag -a ${release_tag} ${release_candidate_tag} -m "[Release] Apache Arrow Release ${version}"
           ^------------^ SC2086 (info): Double quote to prevent globbing and word splitting.
                          ^----------------------^ SC2086 (info): Double quote to prevent globbing and word splitting.

Did you mean:
git tag -a "${release_tag}" "${release_candidate_tag}" -m "[Release] Apache Arrow Release ${version}"

In dev/release/post-01-tag.sh line 35:
git push upstream ${release_tag}
                  ^------------^ SC2086 (info): Double quote to prevent globbing and word splitting.

Did you mean:
git push upstream "${release_tag}"

For more information:
  https://www.shellcheck.net/wiki/SC2086 -- Double quote to prevent globbing ...
```

### What changes are included in this PR?

* SC2086: Quote variables.

### Are these changes tested?

Yes.

### Are there any user-facing changes?

No.
* GitHub Issue: #50670

Authored-by: Hiroyuki Sato <hiroysato@gmail.com>
Signed-off-by: Sutou Kouhei <kou@clear-code.com>