[TASK] Require typo3fluid/fluid:^2.8.0

Minor release update from ^2.7.4 to ^2.8.0:

- main/v13: Require ^2.8.0
- v12: Require ^2.8.0, projects will update
  with next core patch level release
- v11: No change, projects *may* be able to
  update if running PHP ^8.1 and having
  mbstring
- v10: No change, projects won't be able to
  update since core does not allow PHP 8.1

Notable changes:

- Require PHP ^8.1 and mbstring

- Syntax improvement: A comma with spaces and
  line breaks on last fluid "arrays" and inline
  syntax is now parsed as expected.

  <f:variable
    name="myArray" value="{
      0: 'first item',
      1: 'second item',
    }"
  />

  {f:if(
    condition: myVariable,
    then: 'yes',
    else: 'no',
  )}

- Syntax improvement: Resolve multi variable references
  correctly.

  {foo}bar{baz}
  foo.{bar}.{baz}

- PHP 8.1 fix when resolving invalid variable references

  {{notExistingVariable}}

- General performance improvements when resolving variables. This
  boosts templates that access lots of variables which resolve
  to object methods like {object.name} to $object->getName().
  This has measurable impact for instance in the backend "log"
  module when rendering many rows, and reduces overall parsetime
  by about 1/4 in the TypoScript "Active TypoScript" module when
  rendering bigger TypoScript trees like the bootstrap package.

Commands:

> composer req typo3fluid/fluid:^2.8.0
> composer req --no-update typo3fluid/fluid:^2.8.0 -d typo3/sysext/adminpanel
> composer req --no-update typo3fluid/fluid:^2.8.0 -d typo3/sysext/core
> composer req --no-update typo3fluid/fluid:^2.8.0 -d typo3/sysext/fluid
> composer req --no-update typo3fluid/fluid:^2.8.0 -d typo3/sysext/redirects

Change-Id: Iaad13cdd327642b52e9e706997485f95ab951032
Releases: main, 12.4
Resolves: #100812
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78939


Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>