docs: update contribution guidelines to reference main branch (#5426)

* docs: update pull request branch link to main branch in contributing-zh.md

* docs: update pull request branch link to main branch in contributing.md

Author: kirisame-wang

CONTRIBUTING.md

@@ -114,7 +114,7 @@ Flowise has 3 different modules in a single mono repository.
 
     to make sure everything works fine in production.
 
-11. Commit code and submit Pull Request from forked branch pointing to [Flowise master](https://github.com/FlowiseAI/Flowise/tree/master).
+11. Commit code and submit Pull Request from forked branch pointing to [Flowise main](https://github.com/FlowiseAI/Flowise/tree/main).
 
 ## 🌱 Env Variables
 

i18n/CONTRIBUTING-ZH.md

@@ -112,7 +112,7 @@ Flowise 在一个单一的单体存储库中有 3 个不同的模块。
     pnpm start
     ```
 
-11. 提交代码并从指向 [Flowise 主分支](https://github.com/FlowiseAI/Flowise/tree/master) 的分叉分支上提交 Pull Request。
+11. 提交代码并从指向 [Flowise 主分支](https://github.com/FlowiseAI/Flowise/tree/main) 的分叉分支上提交 Pull Request。
 
 ## 🌱 环境变量