Clarify ACL needed for requesting branch

[CtrlZmaster]

Somewhat unintuitively, you need the "Create a ticket" ACL for the fedpkg request-branch command, because it just created this ticket: https://pagure.io/releng/fedora-scm-requests/issue/77929 I never needed to interact with the Pagure API before, so I didn't have any API key before this. I wanted minimal permissions, so I chose "Modify a project" because that sounded reasonable and that's why my previous attempts for requesting branch failed. I was also trying out API keys from the dist-git Pagure instance and project settings... Then I just created the API key with all ACLs and it finally worked - but I wanted to document this as I wasn't able to find any help by searching the internet.

[yselkowitz]

The relevant part of fedpkg --help states:

    set-distgit-token   Updates the fedpkg.distgit API token in
                        ~/.config/rpkg/fedpkg.conf file. Tokens are of length 64 and
                        contain only uppercase and numerical values. The new API token
                        can be generated at:
                        https://src.fedoraproject.org/settings/token/new

It does seem to be an omission in Fedora's docs, but request-branch is in no way specific to ELN. For example, it is used when importing a new package in order to add it to stable branches (and not just rawhide), or when adding an existing package to EPEL.

I think https://docs.fedoraproject.org/en-US/package-maintainers/Installing_Packager_Tools/ may be a better place to mention this.

[CtrlZmaster]

@yselkowitz you're right. Would you consider linking to this page instead if it gets merged: https://pagure.io/fedora-docs/package-maintainer-docs/pull-request/185

But I get it if you want to keep this focused on eln, feel free to close this MR in that case.