[APM Onboarding] Fix NOTES for APM Instrumentation

[liliyadd]

NOTES template has a bug of using snake case formatted Single Step Instrumentation configuration instead of camel case.

With this fix, configuration like

  apm:
    enabled: false
    socketEnabled: true
    instrumentation:
      enabled: true
      disabledNamespaces:
      - default
      enabledNamespaces:
      - datadog
      - rc-tests
      libVersions: []

will result in the error

➜  helm-charts git:(liliya.belaus/fix-ssi-notes) helm install dd2 ./charts/datadog --dry-run --debug -n datadog -f ~/values-test-cluster.yaml
install.go:200: [debug] Original chart version: ""
install.go:217: [debug] CHART PATH: /Users/liliya.belaus/dd/helm-charts/charts/datadog

coalesce.go:220: warning: cannot overwrite table with non table for datadog.datadog.apm.instrumentation.libVersions (map[])
coalesce.go:220: warning: cannot overwrite table with non table for datadog.datadog.apm.instrumentation.libVersions (map[])
Error: INSTALLATION FAILED: execution error at (datadog/templates/NOTES.txt:134:4): The options `datadog.apm.instrumentation.enabledNamespaces` and `datadog.apm.instrumentation.disabledNamespaces` cannot be set together.
helm.go:84: [debug] execution error at (datadog/templates/NOTES.txt:134:4): The options `datadog.apm.instrumentation.enabledNamespaces` and `datadog.apm.instrumentation.disabledNamespaces` cannot be set together.
INSTALLATION FAILED
main.newInstallCmd.func2
	helm.sh/helm/v3/cmd/helm/install.go:147
github.com/spf13/cobra.(*Command).execute
	github.com/spf13/[email protected]/command.go:916
github.com/spf13/cobra.(*Command).ExecuteC
	github.com/spf13/[email protected]/command.go:1044
github.com/spf13/cobra.(*Command).Execute
	github.com/spf13/[email protected]/command.go:968
main.main
	helm.sh/helm/v3/cmd/helm/helm.go:83
runtime.main
	runtime/proc.go:250
runtime.goexit
	runtime/asm_arm64.s:1172

Checklist

[Place an '[x]' (no spaces) in all applicable fields. Please remove unrelated fields.]

• Chart Version bumped
• Documentation has been updated with helm-docs (run: .github/helm-docs.sh)
• CHANGELOG.md has been updated
• Variables are documented in the README.md
• For Datadog Operator chart or value changes update the test baselines (run: make update-test-baselines)