a6f91f70b7
### What this PR does / why we need it? This patch add the versioning policy doc for vllm-ascend Reference: - https://spark.apache.org/versioning-policy.html - https://docs.openstack.org/project-team-guide/stable-branches.html - https://github.com/pytorch/pytorch/blob/main/RELEASE.md ### Does this PR introduce _any_ user-facing change? No ### How was this patch tested? preview: https://vllm-ascend--62.org.readthedocs.build/en/62/ Signed-off-by: Yikun Jiang <yikunkero@gmail.com>