Fixes #971: Add a Protobuf linter to the project

[anandwana001]

Explanation

• Fixes Add a Protobuf linter to the project #971
• Added buf.yaml
• Update config.yaml with new install_buf job
• Proto files lint errors resolved

Checklist

• The PR title starts with "Fix #bugnum: ", followed by a short, clear summary of the changes. (If this PR fixes part of an issue, prefix the title with "Fix part of #bugnum: ...".)
• The PR explanation includes the words "Fixes #bugnum: ..." (or "Fixes part of #bugnum" if the PR only partially fixes an issue).
• The PR follows the style guide.
• The PR does not contain any unnecessary auto-generated code from Android Studio.
• The PR is made from a branch that's not called "develop".
• The PR is made from a branch that is up-to-date with "develop".
• The PR's branch is based on "develop" and not on any other branch.
• The PR is assigned to an appropriate reviewer in both the Assignees and the Reviewers sections.

[vinitamurthi]

Overall looks good! I had a question mainly about why we are removing the except cases. Also I want to wait and see if its running okay in CircleCI before approving so let's wait on that

[vinitamurthi]

I think the linters job is failing while trying to install buf: https://app.circleci.com/pipelines/github/oppia/oppia-android/3415/workflows/c8e3f4af-2b51-4c75-b761-ded3b37fbe3e/jobs/6809/parallel-runs/0/steps/0-104

[BenHenning]

Thanks @anandwana001! This generally LGTM. Just had a few comments.

[anandwana001]

Locally working fine. Need to understand the task generateProto because this is somehow connected with the domain test part and failing non_flaky due to change in proto files.

Changing import "src/main/proto/subtitled_html.proto"; to import "subtitled_html.proto";, fails
and buf says not able to find files
and reverse fails non_flaky saying generateProto fails

[anandwana001]

I think it's done, I checked it over local CircleCI too.

How it seems when linters fail - changed the small c to capitalC in one of the proto file

How it seems when linters passes

[vinitamurthi]

Overall its going on the right track @anandwana001 ! Just a couple things - we want to enforce the enum checks that buf is asking for, so let's not exclude that and instead make those changes in our enums. Otherwise just some nits.

Also note that the non-flaky-tests failed, but I think that's because of a circleCI load issue, can you rerun them and check?

[anandwana001]

Overall its going on the right track @anandwana001 ! Just a couple things - we want to enforce the enum checks that buf is asking for, so let's not exclude that and instead make those changes in our enums. Otherwise just some nits.

Also note that the non-flaky-tests failed, but I think that's because of a circleCI load issue, can you rerun them and check?

Ok, I will rerun and check. Does modifying enums in all these proto files will affect other parts of the project?

[rt4914]

@rt4914 Can you resolve comments on my behalf once @anandwana001 makes the changes?

@vinitamurthi Sure. I will do that.

[rt4914]

Need some clarifications related to proto changes. Also, one of the reasons why the circle ci is failing is because of the changes in proto.

[rt4914]

LGTM. I have added one comment for Sarthak and Vinita.

[vinitamurthi]

LGTM

[vinitamurthi]

Looks good, there are a few unresolved comments though, please wait on that.

[rt4914]

@anandwana001 Resolved all my comments.

[anandwana001]

@anandwana001 Resolved all my comments.

Thank you

[rt4914]

Merging this on behalf of @anandwana001