[Bug] .yarnrc generated in Windows includes yarn_path containing "\\" instead of "/"

[exKAZUu]

• I'd be willing to implement a fix

Describe the bug

.yarnrc generated in Windows includes yarn_path containing "\" instead of "/", e.g., yarn-path ".yarn\\releases\\yarn-berry.js".
However, this causes a problem where a non-Windows environment cannot launch berry as follows.

$ yarn
internal/modules/cjs/loader.js:638
    throw err;
    ^

Error: Cannot find module '/mnt/c/XXX/.yarn\releases\yarn-berry.js'
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:636:15)
    at Function.Module._load (internal/modules/cjs/loader.js:562:25)
    at Function.Module.runMain (internal/modules/cjs/loader.js:831:12)
    at startup (internal/bootstrap/node.js:283:19)
    at bootstrapNodeJSCore (internal/bootstrap/node.js:623:3)

To Reproduce

1. Create a npm package with Yarn v1
2. yarn policies set-version berry

We cannot reproduce this issue in Sherlock because this issue occured only on Windows,

Screenshots

There is no applicable thing.

Environment if relevant (please complete the following information):

• OS: Windows
• Node version v13.3.0
• Yarn version 2.0.0-rc.28

Additional context

Nothing.

[exKAZUu]

Oops, this seems due to https://github.com/yarnpkg/yarn/blob/master/src/cli/commands/policies.js#L158, so should I move this issue into https://github.com/yarnpkg/yarn ...?

[exKAZUu]

Duplicated to yarnpkg/yarn#7777

[exKAZUu]

Fixed in yarnpkg/yarn#7862