Change the delimiter used in commit messages in dependabot commits

[akhilerm]

I am using dependabot enabled via Github. The messages in the commits generated by dependabot has --- used to separate between message and updated-dependencies section. Ref: https://patch-diff.githubusercontent.com/raw/containerd/containerd/pull/11474.patch

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- [Commits](https://github.com/containerd/project-checks/compare/434a07157608eeaa1d5c8d4dd506154204cd9401...800740a80e93c309f9a40903ce26d749ad0909ec)

---                 <=====THIS CAUSES ISSUES
updated-dependencies:
- dependency-name: containerd/project-checks
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
---
 .github/workflows/ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
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Since --- is the delimiter used by git am to separate between the actual diff and the commit message, when the above patch is applied using git am <11474.patch>, the new commit does not have the content from updated-dependencies and the Signed-off-by section. After applying patch

commit 7d4cc9706cd4765e0838f41c67cb1e6d5b86e4e8 (HEAD -> main)
Author: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Date:   Tue Mar 4 07:34:23 2025 +0000

    build(deps): bump containerd/project-checks from 1.1.0 to 1.2.1

    Bumps [containerd/project-checks](https://github.com/containerd/project-checks) from 1.1.0 to 1.2.1.
    - [Commits](https://github.com/containerd/project-checks/compare/434a07157608eeaa1d5c8d4dd506154204cd9401...800740a80e93c309f9a40903ce26d749ad0909ec)

Is there an option to use custom delimiters in the commit message so this issue can be avoided.

[akhilerm]

Moved to #13918