docs: Update README devtool tag

[jonas-martinez]

Closes #

Description of the changes

Update the README so that the way to set the devtool tag for an application is up to date with the current CLI's way of doing it.

Checklist

• [x] I didn't over-scope my PR
• [x] My PR title matches the commit convention
• [x] I did not include breaking changes
• [x] I made my own code-review before requesting one

I included unit tests that cover my changes

• [ ] 👍 yes
• [x] 🙅 no, because they aren't needed
• [ ] 🙋 no, because I need help

I added/updated the documentation about my changes

• [ ] 📜 README.md
• [ ] 📕 docs/*.md
• [ ] 📓 docs.lenra.io
• [x] 🙅 no documentation needed

Technical highlight/advice

[taorepoara]

Don't forget the check list

[shiipou]

:tada: This PR is included in version 1.0.0-beta.85 :tada:

The release is available on:

• GitHub release
• v1.0.0-beta.85

Your semantic-release bot :package::rocket:

[shiipou]

:tada: This PR is included in version 1.0.0-alpha.4 :tada:

The release is available on:

• GitHub release
• v1.0.0-alpha.4

Your semantic-release bot :package::rocket: