[Doc] Add feature branch policy (#2432)

### What this PR does / why we need it?

This patch add the feature branch policy.

After this patch: maintainers are allowed to create a feature branch.
Feature branches are used for collaboration and must include an RFC
link, merge plan and mentor info.

### Does this PR introduce _any_ user-facing change?

No

### How was this patch tested?

CI passed

- vLLM version: v0.10.0
- vLLM main:
7be5d113d8

Signed-off-by: Yikun Jiang <yikunkero@gmail.com>

.github/ISSUE_TEMPLATE/750-RFC.yml

@@ -40,7 +40,7 @@ body:
   attributes:
     label: Any Other Things.
     description: >
-      Any other things you would like to mention.
+      Any other things you would like to mention, such as feature branch request.
   validations:
     required: false
 - type: markdown

README.md

@@ -77,6 +77,7 @@ Below is maintained branches:
 | v0.7.1-dev | Unmaintained | Only doc fixed is allowed |
 | v0.7.3-dev | Maintained   | CI commitment for vLLM 0.7.3 version, only bug fix is allowed and no new release tag any more. |
 | v0.9.1-dev | Maintained   | CI commitment for vLLM 0.9.1 version |
+| rfc/feature-name | Maintained | [Feature branches](https://vllm-ascend.readthedocs.io/en/latest/community/versioning_policy.html#feature-branches) for collaboration |
 
 Please refer to [Versioning policy](https://vllm-ascend.readthedocs.io/en/latest/community/versioning_policy.html) for more details.
 

README.zh.md

@@ -76,6 +76,7 @@ vllm-ascend有主干分支和开发分支。
 | v0.7.1-dev | Unmaintained | 只允许文档修复 |
 | v0.7.3-dev | Maintained | 基于vLLM v0.7.3版本CI看护, 只允许Bug修复，不会再发布新版本 |
 | v0.9.1-dev | Maintained | 基于vLLM v0.9.1版本CI看护 |
+|rfc/feature-name| Maintained | 为协作创建的[特性分支](https://vllm-ascend.readthedocs.io/en/latest/community/versioning_policy.html#feature-branches) |
 
 请参阅[版本策略](https://vllm-ascend.readthedocs.io/en/latest/community/versioning_policy.html)了解更多详细信息。
 

docs/source/community/versioning_policy.md

@@ -84,6 +84,17 @@ Usually, each minor version of vLLM (such as 0.7) will correspond to a vLLM Asce
 | v0.7.3-dev | Maintained   | CI commitment for vLLM 0.7.3 version |
 | v0.7.1-dev | Unmaintained | Replaced by v0.7.3-dev               |
 
+### Feature branches
+
+| Branch     | Status       | RFC link                              | Merge plan | Mentor |
+|------------|--------------|---------------------------------------|------------|--------|
+
+- Branch: The feature branch should be created with a prefix `rfc/` followed by the feature name, such as `rfc/feature-name`.
+- Status: The status of the feature branch is `Maintained` until it is merged into the main branch or deleted.
+- RFC link: The feature branch should be created with a corresponding RFC issue. The creation of a feature branch requires an RFC and approval from at least two maintainers.
+- Merge plan: The final goal of a feature branch is to merge it into the main branch. If it exceeds 3 months, the mentor maintainer should evaluate whether to delete the branch.
+- Mentor: The mentor should be a vLLM Ascend maintainer who is responsible for the feature branch.
+
 ### Backward compatibility
 
 For main branch, vLLM Ascend should works with vLLM main branch and latest 1 or 2 release version. So to ensure the backward compatibility, we will do the following: