Add SAG SONiC Yang

[superchild]

Why I did it

For static anycast gateway feature, add related yang model. Refer to SAG HLD#837

Signed-off-by: Jimi Chen [email protected]

How I did it

• Defined sonic-static-anycast-gateway.yang model, and modify sonic-vlan.yang for new added field.
• Add sonic-yang-model/sonic-yang-mgmt unit test case

How to verify it

• build sonic_yang_models-1.0-py3-none-any.whl /sonic_yang_mgmt-1.0-py3-none-any.whl successfully

Which release branch to backport (provide reason below if selected)

• [ ] 201811
• [ ] 201911
• [ ] 202006
• [ ] 202012
• [ ] 202106

Description for the changelog

A picture of a cute animal (not mandatory but encouraged)

[superchild]

@lguohan Could you please help to review the code? The related CLI sonic-utilities#1887 code change doesn't have reviewer yet, could you please help to assign someone to review? Thanks.

[superchild]

@venkatmahalingam please help to review the updated version, thanks.

[superchild]

@venkatmahalingam @lguohan Can you please help to check and review? Thanks.

[superchild]

@qiluo-msft @venkatmahalingam Could you please help to review the change?

[superchild]

@qiluo-msft @venkatmahalingam @lguohan Could you please help to review again? Thanks.

[qiluo-msft]

Could you merge latest master? It will also retrigger the PR checkers.

[zhangyanzhao]

@superchild can you please sign-off the EasyCLA? This merge is blocked by it. Thanks.

[superchild]

@zhangyanzhao I already signed the EasyCLA, there're some conflicts existed. I'll fix the conflicts soon.

[superchild]

@zhangyanzhao Conflict is resolved, I think it needs reviewer to approve running workflows.

[liat-grozovik]

@venkatmahalingam i see you had comments, can you please review following comments handling so i can go a head and merge

[liat-grozovik]

@superchild please handle conflicts

[superchild]

@liat-grozovik
I don't work on this project anymore and don't have related build machine to test.
I'll suggest someone can help to finish this or send the other PR.