Fix composer lock not up to date

[symfonyaml]

Problem

When I follow the instructions to install the demo project with the git clone command, I have the following error

Installing dependencies from lock file (including require-dev)
Verifying lock file contents can be installed on current platform.
Warning: The lock file is not up to date with the latest changes in composer.json. You may be getting outdated dependencies. It is recommended that you run `composer update` or `composer update <package name>`.
- Required package "twbs/bootstrap" is not present in the lock file.
This usually happens when composer files are incorrectly merged or the composer.json file is manually edited.
Read more about correctly resolving merge conflicts https://getcomposer.org/doc/articles/resolving-merge-conflicts.md
and prefer using the "require" command over editing the composer.json file directly

Reproduce

Script taken from README Installation guide

git clone https://github.com/symfony/demo.git my_project
cd my_project/
composer install

Solution

I run a composer update and pushed the composer lock file

[javiereguiluz]

Thanks @symfonyaml and sorry for this issue.

Your proposed solution is correct but, we just merged #1572 to update the project dependencies to fix a security vulnerability. So, that also fixed (indirectly) the problem reported in this pull request.

That's why we are closing this one without merging it. Thanks.

[xabbuh]

I think if @symfonyaml rebases these changes and amends the commit to something like "update dependencies" it's still worth to merge it.

[javiereguiluz]

Let's reopen then!

[symfonyaml]

I think if @symfonyaml rebases these changes and amends the commit to something like "update dependencies" it's still worth to merge it.

@xabbuh done in #1573