feat: migrate recipes

Author: tongyx361

.github/CODEOWNERS

@@ -3,10 +3,6 @@
 /docs/slang_multiturn @zhaochenyang20 @SwordFaith
 /docs/ascend_tutorial @FightingZhen
 
-/recipe/dapo @tongyx361 @PeterSH6 @vermouth1992 @tardis-key @FightingZhen @ji-huazhong
-/recipe/spin @zhaochenyang20
-/recipe/sppo @zhaochenyang20
-
 /third_party/sglang @zhaochenyang20 @SwordFaith
 /third_party/vllm @PeterSH6 @wuxibin89
 

.github/PULL_REQUEST_TEMPLATE.md

@@ -38,3 +38,4 @@
 - [ ] Add / Update [the documentation](https://github.com/volcengine/verl/tree/main/docs).
 - [ ] Add unit or end-to-end test(s) to [the CI workflow](https://github.com/volcengine/verl/tree/main/.github/workflows) to cover all the code. If not feasible, explain why: ...
 - [ ] Once your PR is ready for CI, send a message in [the `ci-request` channel](https://verl-project.slack.com/archives/C091TCESWB1) in [the `verl` Slack workspace](https://join.slack.com/t/verl-project/shared_invite/zt-3855yhg8g-CTkqXu~hKojPCmo7k_yXTQ). (If not accessible, please try [the Feishu group (飞书群)](https://applink.larkoffice.com/client/chat/chatter/add_by_link?link_token=772jd4f1-cd91-441e-a820-498c6614126a).)
+- [ ] If your PR is related to the `recipe` submodule, please also update the reference to the submodule commit via `git submodule update --remote` or `cd recipe && git pull origin main`.