[!222] update dune-composites.md to releases/2.6

Merge branch 'master' into 'master'

See merge request [!222]

  [!222]: Noneinfrastructure/dune-website/merge_requests/222
4 jobs from master in 24 minutes and 47 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Hugo
passed #77285
website
hugo-deploy

00:02:06

 
  Documentation
failed #77286
website
doxygen-deploy

00:22:40

passed #77287
website
sphinx-deploy

00:06:21

 
  Deploy
skipped #77288
website-deploy
deploy
 
Name Stage Failure
failed
doxygen-deploy Documentation
[INFO    ] ciwebsitebuilder: Creating worktree for dune-composites@releases/2.5 in /builds/infrastructure/dune-website/tmp/doxygen/doxygen/dune-composites/release-2.5/dune-composites
[INFO ] ciwebsitebuilder: Doxygen: Running doxygen Doxyfile in /builds/infrastructure/dune-website/tmp/doxygen/doxygen/dune-composites/release-2.5/doc
[NOTICE ] ciwebsitebuilder: Building Doxygen docset /doxygen/dune-composites/release-2.6 (content/modules/dune-composites.md)
[INFO ] ciwebsitebuilder: Creating worktree for dune-composites@releases/2.6 in /builds/infrastructure/dune-website/tmp/doxygen/doxygen/dune-composites/release-2.6/dune-composites
[CRITICAL] ciwebsitebuilder: Error running git worktree add -f /builds/infrastructure/dune-website/tmp/doxygen/doxygen/dune-composites/release-2.6/dune-composites releases/2.6 in /builds/infrastructure/dune-website/repositories/dune-composites.git
fatal: invalid reference: releases/2.6

Aborted!
ERROR: Job failed: exit code 1