Add support for ppc64le

[matzew]

Summary

buildpacks has already support for a number architectures, including s390x. There is currently no image here for ppc64le.
Being able to use buildpacks on this platform would allow a developers to not need to care as much about what architecure, when running their code.

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Proposal

updating the Makefile and the gh hooks for the build, like here:

On branch add_ppc64le_arch
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git restore <file>..." to discard changes in working directory)
	modified:   .github/workflows/build.yml
	modified:   .github/workflows/draft-release.yml
	modified:   .github/workflows/post-release.yml
	modified:   Makefile