Yamlgen: Upgrade to serde-yaml 0.9

[jpmcb]

Issue number:

Closes #333
Closes #277

Description of changes:

- Captures formatting changes introduced in new versions of serde.
- Adds `---` delimiters explicitly when generating yaml manifest since
  serde-yaml no longer includes those.
- Upgrades schemars to 0.8.11 which no longer breaks enum serialization
  when combined with kube-rs 0.76
- Removes outdated kube-rs ignore in deny.toml
- Adds a dump of the git diff in the "Evaluate git clean" GitHub action
  in order to see what's changed directly from the action failure.

Signed-off-by: John McBride <jpmmcb@amazon.com>

Testing done:

Integration tests running ... please hold!

Terms of contribution:

By submitting this pull request, I agree that this contribution is dual-licensed under the terms of both the Apache License, version 2.0, and the MIT license.

[jpmcb]

Force pushed to add

• Upgrade to schemars 0.8.11
• Remove an unnecessary line in the deny.toml for an outdated version of kube-rs

[jpmcb]

Integration tests passed!

❯ k get brs -A
NAMESPACE                 NAME                                                STATE   VERSION   TARGET STATE   TARGET VERSION   CRASH COUNT
brupop-bottlerocket-aws   brs-ip-192-168-138-240.us-west-2.compute.internal   Idle    1.10.1    Idle                            0
brupop-bottlerocket-aws   brs-ip-192-168-145-184.us-west-2.compute.internal   Idle    1.10.1    Idle                            0
brupop-bottlerocket-aws   brs-ip-192-168-159-48.us-west-2.compute.internal    Idle    1.10.1    Idle                            0

Marking ready for review

[webern]

while yamlgen still exists...

[stmcginnis]

Merge conflicts now...

[jpmcb]

Force pushed to address merge-conflicts