pr-template-checklist-addendum (#2165)

Author: jschaul

.github/pull_request_template.md

@@ -2,6 +2,7 @@
 
  - [ ] The **PR Title** explains the impact of the change.
  - [ ] The **PR description** provides context as to why the change should occur and what the code contributes to that effect. This could also be a link to a JIRA ticket or a Github issue, if there is one.
+ - [ ] If this PR changes development workflow or dependencies, they have been A) automated and B) documented under docs/developer/. All efforts have been taken to minimize development setup breakage or slowdown for co-workers.
  - [ ] If HTTP endpoint paths have been added or renamed, the **endpoint / config-flag checklist** (see Wire-employee only backend [wiki page](https://github.com/zinfra/backend-wiki/wiki/Checklists)) has been followed.
  - [ ] If a cassandra schema migration has been added, I ran **`make git-add-cassandra-schema`** to update the cassandra schema documentation.
  - [ ] **changelog.d** contains the following bits of information ([details](https://github.com/wireapp/wire-server/blob/develop/docs/developer/changelog.md)):