feat: Add mxinden as maintainer to universal connectivity

[mxinden]

Summary

Add myself as maintainer to the universal connectivy repository in order to push to libp2p/universal-connectivity#3.

Why do you need this?

Want to push a fix for the missing SUBSCRIBE.

What else do we need to know?

DRI: myself

Reviewer's Checklist

• It is clear where the request is coming from (if unsure, ask)
• All the automated checks passed
• The YAML changes reflect the summary of the request
• The Terraform plan posted as a comment reflects the summary of the request

[github-actions]

Before merge, verify that all the following plans are correct. They will be applied as-is after the merge.

Terraform plans

libp2p

Terraform used the selected providers to generate the following execution
plan. Resource actions are indicated with the following symbols:
  + create

Terraform will perform the following actions:

  # github_repository_collaborator.this["universal-connectivity:mxinden"] will be created
  + resource "github_repository_collaborator" "this" {
      + id                          = (known after apply)
      + invitation_id               = (known after apply)
      + permission                  = "maintain"
      + permission_diff_suppression = false
      + repository                  = "universal-connectivity"
      + username                    = "mxinden"
    }

Plan: 1 to add, 0 to change, 0 to destroy.