fix(pr create): clarify refspec to push to correct branch in the event of a conflicting tag

[arunsathiya]

Fixes #8572

Description

With this patch, pr create command will correctly specify the refspec to push the changes, to the correct branch, in the event of a conflicting tag.

How to test

• Have a local git repository with an origin (which can be a fork of an upstream)
• Ensure local repo and origin have a tag with the same name as the branch, assuming main (git tag main && git push origin refs/tags/main, as an example)
• Make changes in the main branch
• Set upstream as default: gh repo set-default
• Create PR with gh pr create --title value
• Ensure that the PR creation goes through as expected

Result

Should be okay like below:

/Users/arun/go/src/cli/bin/gh pr create
? Where should we push the 'main' branch? arunsathiya/test

Creating pull request for arunsathiya:main into main in avydun/test

? Title test commit
? Body <Received>
? What's next? Submit
To github.com:arunsathiya/test.git
   1712662..fc6b8f2  HEAD -> main
branch 'main' set up to track 'origin/main'.
https://github.com/avydun/test/pull/2

[williammartin]

LGTM!

➜  test-repo git:(heads/main) ✗ git checkout -b 8572-triage
Switched to a new branch '8572-triage'

➜  test-repo git:(8572-triage) ✗ git tag 8572-triage

➜  test-repo git:(heads/8572-triage) ✗ git push --tags
Total 0 (delta 0), reused 0 (delta 0), pack-reused 0
^[[ATo https://github.com/williammartin/test-repo.git
 * [new tag]         8572-triage -> 8572-triage

➜  test-repo git:(heads/8572-triage) ✗ git push -u origin heads/8572-triage
Total 0 (delta 0), reused 0 (delta 0), pack-reused 0
remote:
remote: Create a pull request for '8572-triage' on GitHub by visiting:
remote:      https://github.com/williammartin/test-repo/pull/new/8572-triage
remote:
To https://github.com/williammartin/test-repo.git
 * [new branch]      8572-triage -> 8572-triage
branch '8572-triage' set up to track 'origin/8572-triage'.

➜  test-repo git:(heads/8572-triage) ✗ touch a && git add . && git commit -m "add triage file"
[8572-triage ccc6ba3] add triage file
 2 files changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 a
 create mode 100644 example.txt

➜  test-repo git:(heads/8572-triage) ~/workspace/cli/bin/gh pr create --title "Example" -F example.txt
? Where should we push the '8572-triage' branch? williammartin/test-repo

Creating pull request for 8572-triage into main in williammartin/test-repo

To https://github.com/williammartin/test-repo.git
   1a79414..ccc6ba3  HEAD -> 8572-triage
branch '8572-triage' set up to track 'origin/8572-triage'.
https://github.com/williammartin/test-repo/pull/3