add help for tls prerequisite for ingress.yaml

[yogin16]

What this PR does / why we need it: conveys the prerequisite that to use grpc backend we need to have tls setup

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #

Special notes for your reviewer:

[k8s-ci-robot]

Thanks for your pull request. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

📝 Please follow instructions at https://git.k8s.io/community/CLA.md#the-contributor-license-agreement to sign the CLA.

It may take a couple minutes for the CLA signature to be fully registered; after that, please reply here with a new comment and we'll verify. Thanks.

---

• If you've already signed a CLA, it's possible we don't have your GitHub username or you're using a different email address. Check your existing CLA data and verify that your email is set on your git commits.
• If you signed the CLA as a corporation, please sign in with your organization's credentials at https://identity.linuxfoundation.org/projects/cncf to be authorized.
• If you have done the above and are still having issues with the CLA being reported as unsigned, please email the CNCF helpdesk: helpdesk@rt.linuxfoundation.org

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository. I understand the commands that are listed here.

[yogin16]

/check-cla

[antoineco]

conveys the prerequisite that to use grpc backend we need to have tls setup

Which is true, GRPC uses http2 and ingress-nginx requires TLS to be enabled to use http2.

[codecov-io]

Codecov Report

Merging #2806 into master will increase coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2806      +/-   ##
==========================================
+ Coverage   47.33%   47.34%   +0.01%     
==========================================
  Files          75       75              
  Lines        5413     5413              
==========================================
+ Hits         2562     2563       +1     
+ Misses       2527     2525       -2     
- Partials      324      325       +1

Impacted Files	Coverage Δ
internal/watch/file_watcher.go	84.61% <0%> (+3.84%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 96c289b...ef69df6. Read the comment docs.

[yogin16]

/assign @antoineco

[aledbf]

@yogin16 please don't assign PRs manually

[yogin16]

sorry, about that. (first pr)
confusion because the bot said

please assign additional approvers

I now get that the checks needs to say ready before that.

[antoineco]

Indeed, besides what do you think about my comment above?

[aledbf]

/lgtm
/approve

[aledbf]

@yogin16 thanks!

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: aledbf, yogin16

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [aledbf]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment