ci(cancel-previous-workflows): use pull_request_target

[kenji-miyake]

Description

According to the documentation, it won't work with PRs from forks.
https://github.com/styfle/cancel-workflow-action#advanced-pull-requests-from-forks

I guess pull_request_target can be used instead of workflow_call.

Related?: styfle/cancel-workflow-action#139

Pre-review checklist for the PR author

The PR author must check the checkboxes below when creating the PR.

• I've confirmed the contribution guidelines.
• The PR follows the pull request guidelines.

In-review checklist for the PR reviewers

The PR reviewers must check the checkboxes below before approval.

• The PR follows the pull request guidelines.

Post-review checklist for the PR author

The PR author must check the checkboxes below before merging.

• There are no open discussions or they are tracked via tickets.

After all checkboxes are checked, anyone who has write access can merge the PR.

[kenji-miyake]

I'll test this in another PR.

-> #1743

[kenji-miyake]

Before: https://github.com/autowarefoundation/autoware.universe/runs/8108661116?check_suite_focus=true

Found 5 runs total.
Found 1 runs to cancel.
Canceling run:  {
  id: 2961952881,
  head_sha: '38a9242a26413ad3b1a8edc491de86807b3ae900',
  status: 'in_progress',
  html_url: 'https://github.com/autowarefoundation/autoware.universe/actions/runs/2961952881'
}
Error while canceling workflow_id 194[79](https://github.com/autowarefoundation/autoware.universe/runs/8108661116?check_suite_focus=true#step:2:80)065: Resource not accessible by integration

Error while canceling workflow_id 19479066: Resource not accessible by integration

After: https://github.com/autowarefoundation/autoware.universe/runs/8108521086?check_suite_focus=true

Cancel run 2962099893 responded with status 202
Canceling run:  {
  id: 2962093970,
  head_sha: 'fe97dd74953ceb99affa9e6593b7c00f67e3540c',
  status: 'in_progress',
  html_url: 'https://github.com/autowarefoundation/autoware.universe/actions/runs/2962093970'
}
Cancel run 2962093970 responded with status 202

Cancel run 2962093970 responded with status 202

Cancel run 2962093970 responded with status 202

Cancel run 2962093970 responded with status 202

Cancel run 2962093970 responded with status 202

Cancel run 2962093970 responded with status 202

Cancel run 2962093970 responded with status 202

Cancel Complete.