Add Mogost as member

[tim-schilling]

Closes django-commons/membership#36

[github-actions]

Terraform plan in terraform
With var files: terraform/production/org.tfvars terraform/production/repositories.tfvars
With variables: github_token = (sensitive value)

Plan: 2 to add, 1 to change, 0 to destroy.

Terraform used the selected providers to generate the following execution
plan. Resource actions are indicated with the following symbols:
+   create
!~  update in-place

Terraform will perform the following actions:

  # github_membership.this["Mogost"] will be created
+   resource "github_membership" "this" {
+       downgrade_on_destroy = false
+       etag                 = (known after apply)
+       id                   = (known after apply)
+       role                 = "member"
+       username             = "Mogost"
    }

  # github_membership.this["maerteijn"] will be created
+   resource "github_membership" "this" {
+       downgrade_on_destroy = false
+       etag                 = (known after apply)
+       id                   = (known after apply)
+       role                 = "member"
+       username             = "maerteijn"
    }

  # github_repository.this["django-tasks-scheduler"] will be updated in-place
!~  resource "github_repository" "this" {
        id                          = "django-tasks-scheduler"
!~      merge_commit_message        = "PR_TITLE" -> "PR_BODY"
!~      merge_commit_title          = "MERGE_MESSAGE" -> "PR_TITLE"
        name                        = "django-tasks-scheduler"
#        (35 unchanged attributes hidden)

#        (1 unchanged block hidden)
    }

Plan: 2 to add, 1 to change, 0 to destroy.

📝 Plan generated in Plan org changes and list them in a PR #64