Repository: create-react-app
Issue: `npx create-react-app my-app` commits .yarn directory with all the dependecines to git
Labels: needs triage,issue: bug report

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### Describe the bug

Running `npx create-react-app my-app` creates a `.yarn` directory with about 80 megabytes of dependencies and commits it to git.


### Did you try recovering your dependencies?

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  Please paste the output of `npm --version` and/or `yarn --version` to confirm.
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Not related to issue


### Which terms did you search for in User Guide?

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(Write your answer here if relevant.)

### Environment


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  This enables the maintainers quickly reproduce the issue and give feedback.

  Run the following command in your React app's folder in terminal.
  Note: The result is copied to your clipboard directly.

  `npx create-react-app --info`

  Paste the output of the command in the section below.
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```
Environment Info:

  current version of create-react-app: 4.0.3
  running from /Users/xxx/node_modules/create-react-app

  System:
    OS: macOS 10.15.7
    CPU: (8) x64 Intel(R) Core(TM) i7-4870HQ CPU @ 2.50GHz
  Binaries:
    Node: 16.2.0 - /usr/local/bin/node
    Yarn: 2.4.1 - /usr/local/bin/yarn
    npm: 7.14.0 - /usr/local/bin/npm
  Browsers:
    Chrome: Not Found
    Edge: Not Found
    Firefox: Not Found
    Safari: 14.1
  npmPackages:
    react: Not Found
    react-dom: Not Found
    react-scripts: Not Found
  npmGlobalPackages:
    create-react-app: Not Found
```

### Steps to reproduce

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(Write your steps here:)

1. `npx create-react-app my-app`

```
du -h .yarn
...
4.0K	.yarn/unplugged/core-js-pure-npm-3.9.0-fed8ed49b8/node_modules/core-js-pure/es/weak-set
116K	.yarn/unplugged/core-js-pure-npm-3.9.0-fed8ed49b8/node_modules/core-js-pure/es/string/virtual
256K	.yarn/unplugged/core-js-pure-npm-3.9.0-fed8ed49b8/node_modules/core-js-pure/es/string
4.0K	.yarn/unplugged/core-js-pure-npm-3.9.0-fed8ed49b8/node_modules/core-js-pure/es/set
 16K	.yarn/unplugged/core-js-pure-npm-3.9.0-fed8ed49b8/node_modules/core-js-pure/es/array-buffer
1.3M	.yarn/unplugged/core-js-pure-npm-3.9.0-fed8ed49b8/node_modules/core-js-pure/es
1.4M	.yarn/unplugged/core-js-pure-npm-3.9.0-fed8ed49b8/node_modules/core-js-pure/modules
136K	.yarn/unplugged/core-js-pure-npm-3.9.0-fed8ed49b8/node_modules/core-js-pure/proposals
7.0M	.yarn/unplugged/core-js-pure-npm-3.9.0-fed8ed49b8/node_modules/core-js-pure
7.0M	.yarn/unplugged/core-js-pure-npm-3.9.0-fed8ed49b8/node_modules
7.0M	.yarn/unplugged/core-js-pure-npm-3.9.0-fed8ed49b8
 30M	.yarn/unplugged
 76M	.yarn
```

```
du -h .git
...
 60K	.git/hooks
4.0K	.git/refs/heads
  0B	.git/refs/tags
4.0K	.git/refs
 55M	.git
```

`.gitignore` should probably contain `/.yarn`, but it doesn't.
```
cat .gitignore 
# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.

# dependencies
/node_modules
/.pnp
.pnp.js

# testing
/coverage

# production
/build

# misc
.DS_Store
.env.local
.env.development.local
.env.test.local
.env.production.local

npm-debug.log*
yarn-debug.log*
yarn-error.log*
```

```
git log .yarn/install-state.gz | cat
commit 2b67c7c8cc70c565ec4082840ae64a2115adb873
Author: xxx
Date:   Tue May 25 11:25:51 2021 +0300

    Initialize project using Create React App
```

### Expected behavior

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I expect that packages/dependencies are not committed to git.
Either `.yarn` directory should be added to `.gitignore` or `npx` should use `npm` to install packages.

### Actual behavior

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  Is something broken, or not behaving as you expected?
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After running `npx create-react-app my-app` there bunch of packages committed to git.

### Reproducible demo

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(Paste the link to an example project and exact instructions to reproduce the issue.)

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