fix: prevent crash due to unresolved alias in yaml

[stefreak]

What this PR does / why we need it:

• chore(deps): update yaml to 2.3.2
• fix: prevent crash due to unresolved alias in yaml
• improvement: use loadAndValidateYaml for both kubernetes manifests and garden configs
• test: add tests for loadAndValidateYaml
• improvement: eliminate explicit any in loadAndValidateYaml

Which issue(s) this PR fixes:

Fixes #5186

Special notes for your reviewer:
This is a workaround for possible upstream bug described in eemeli/yaml#497

Manual test looks like this:

% gdev deploy  
Deploy 🚀 

Garden v0.13 (Bonsai) is a major release with significant changes. Please help us improve it by reporting any issues/bugs here:
https://go.garden.io/report-bonsai
→ Run garden util hide-warning 0.13-bonsai to disable this warning.
ℹ garden               → Running in Garden environment local.default
Could not parse frontend.garden.yml in directory /Users/steffen/work/github/garden/examples/demo-project/frontend as valid YAML: YAMLException: unidentified alias "foobar" (2:14)

 1 | kind: Build
 2 | name: *foobar
------------------^
 3 | description: Frontend service container image
 4 | type: container

and for a kubernetes manifest:

% gdev deploy redis
Deploy 🚀

Garden v0.13 (Bonsai) is a major release with significant changes. Please help us improve it by reporting any issues/bugs here:
https://go.garden.io/report-bonsai
→ Run garden util hide-warning 0.13-bonsai to disable this warning.
ℹ garden               → Running in Garden environment local.default
ℹ cloud-dashboard      → View command results at: https://app.garden.io/go/command/RWwxXGFhUl

ℹ providers            → Getting status...
✔ providers            → Cached (took 0.8 sec)
ℹ providers            → Run with --force-refresh to force a refresh of provider statuses.
ℹ graph                → Resolving actions and modules...
✔ graph                → Done (took 0 sec)
ℹ deploy.redis         → missing
ℹ deploy.redis         → Deploying version v-96dc07041c...
✖ deploy.redis         → Failed (took 0 sec)
✖ deploy.redis         → Failed processing Deploy type=kubernetes name=redis (took 0.06 sec). This is what happened:

────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
Could not parse redis.yml in directory /Users/steffen/work/github/garden/examples/kubernetes-deploy/redis (specified in Deploy type=kubernetes name=redis) as valid YAML: YAMLException: unidentified alias "bar" (4:10)

 1 | ---
 2 | # Source: redis/templates/secret.yaml
 3 | apiVersion: v1
 4 | foo: *bar
--------------^
 5 | kind: Secret
 6 | metadata:
────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
1 deploy action(s) failed!

See .garden/error.log for detailed error message

[eysi09]

Great tests!

[eysi09]

This looks good to me!

Thanks for adding the tests, great work!