fix: remove duplicate filecoin-pin collaborator

[rjan90]

Summary

• remove juliangruber from the filecoin-pin push collaborators because they are already listed as admin
• keep both FilOzzy and juliangruber as admin-only entries for filecoin-pin

Context

This fixes the Terraform duplicate object key failure from the Apply run after #211 merged:
https://github.com/filecoin-project/github-mgmt/actions/runs/27330972116/job/80743094826

Terraform reported the duplicate key as filecoin-pin:juliangruber.

Validation

• ruby -ryaml -e 'cfg=YAML.load_file("github/filecoin-project.yml"); c=cfg.dig("repositories","filecoin-pin","collaborators") || {}; %w[FilOzzy juliangruber].each { |u| raise "#{u} missing admin" unless (c["admin"] || []).include?(u); %w[maintain push triage pull].each { |p| raise "#{u} duplicate #{p}" if (c[p] || []).include?(u) } }; puts "filecoin-pin admin-only collaborators OK"'\n- git diff --check

[github-actions]

The following access changes will be introduced as a result of applying the plan:

Access Changes

User filozzy:
  - will have the permission to filecoin-pin change from push to admin
User juliangruber:
  - will have the permission to filecoin-pin change from push to admin

[github-actions]

Before merge, verify that all the following plans are correct. After merge, Apply will regenerate the plans from the merged commit and continue only if they match.

Terraform plans

filecoin-project

Terraform used the selected providers to generate the following execution
plan. Resource actions are indicated with the following symbols:
-/+ destroy and then create replacement

Terraform will perform the following actions:

  # github_repository_collaborator.this["filecoin-pin:filozzy"] must be replaced
-/+ resource "github_repository_collaborator" "this" {
      ~ id                          = "filecoin-pin:FilOzzy" -> (known after apply)
      + invitation_id               = (known after apply)
      ~ permission                  = "push" -> "admin" # forces replacement
      + permission_diff_suppression = false
        # (2 unchanged attributes hidden)
    }

  # github_repository_collaborator.this["filecoin-pin:juliangruber"] must be replaced
-/+ resource "github_repository_collaborator" "this" {
      ~ id                          = "filecoin-pin:juliangruber" -> (known after apply)
      + invitation_id               = (known after apply)
      ~ permission                  = "push" -> "admin" # forces replacement
      + permission_diff_suppression = false
        # (2 unchanged attributes hidden)
    }

Plan: 2 to add, 0 to change, 2 to destroy.