Swarm: Add schema 3.11, and Allow additional properties in build

[laurazard]

- What I did

Since Swarm does not use the build section, there's no reason to validate properties here.
This makes it so we don't have to keep updating the schema in the CLI to support properties added in the Compose Spec for build, and does not imply any new feature support since Swarm does not consider this section.

- How I did it

Update the schema in the CLI to allow additionalProperties in build.

- How to verify it

Write a Compose file such as

services:
  a:
    image: alpine
    build:
      whatever: "meow"

and deploy it with docker stack deploy -c <file> [name]

- Description for the changelog

related:

• closes [BUG] Additional property additional_contexts is not allowed when using docker stack deploy #4183
• supersedes / closes Allow extensions in build field in docker-compose.yaml schema #4113

- A picture of a cute animal (not mandatory but encouraged)

[thaJeztah]

Looks like there's a failure somewhere

#19 80.15 === FAIL: cli/compose/loader TestLoad (0.00s)
#19 80.15     loader_test.go:238: assertion failed: 3.10 (sampleConfig.Version string) != 3.11 (actual.Version string)

[laurazard]

Yup! Sorry, should have left this as a draft, I wanted to look at the tests and add some but started looking at something else in the meantime and got distracted 😅

[thaJeztah]

LGTM