update required minimum TwigBridge version

To be able to use `Twig_SimpleFunction` in `AssetsExtension`, Twig has
to be present in version 1.12 or higher. The TwigBridge only enforces
this Twig version as of version 2.3.10.
minor #13030 [TwigBundle] update required minimum TwigBridge version (xabbuh)

This PR was submitted for the 2.7 branch but it was merged into the 2.3 branch instead (closes #13030).

Discussion
----------

[TwigBundle] update required minimum TwigBridge version

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

To be able to use `Twig_SimpleFunction` in `AssetsExtension`, Twig has
to be present in version 1.12 or higher. The TwigBridge only enforces
this Twig version as of version 2.3.10.

Commits
-------

cb351a6 update required minimum TwigBridge version