Convert datetime coffeescript spec to ES6

What does this MR do?

Converts the last remnant coffeescript file to ES6

Are there points in the code the reviewer needs to double check?

None

Why was this MR needed?

Because we aren't using coffeescript anymore

What are the relevant issue numbers?

#21472 (closed)

Screenshots (if relevant)

None

Does this MR meet the acceptance criteria?

• CHANGELOG entry added
• Tests
  • All builds are passing
• Conform by the style guides
• Branch has no merge conflicts with master (if you do - rebase it please)
• Squashed related commits together

Added 5 commits:

• 5ff73115...1bf2fe27 - 4 commits from branch gitlab-org:master
• 628bc9b1 - Convert datetime coffeescript spec to ES6

Added 1 commit:

• 5616c55e - Convert datetime coffeescript spec to ES6

Added ~164274 backstage javascript labels

@annabeldunstone could you take a look?

Reassigned to @alfredo1

@fatihacet could you take a look?

Added 379 commits:

• 5616c55e...aab00fa1 - 378 commits from branch gitlab-org:master
• 662d5b90 - Convert datetime coffeescript spec to ES6

@fatihacet added ;

Resolved all discussions

Added 33 commits:

• 662d5b90...33a367e8 - 32 commits from branch gitlab-org:master
• d8d699ff - Convert datetime coffeescript spec to ES6

@ClemMakesApps

Status changed to merged

mentioned in commit 00772f75

Milestone changed to %8.12

mentioned in issue #21472 (closed)

Mentioned in commit pfjason/gitlab-ce@00772f75