v0.3.12

Trixi2Vtk v0.3.12

Diff since v0.3.11

Merged pull requests:

• mention that Trixi2Vtk.jl also works with newer Julia versions (#73) (@ranocha)
• CompatHelper: bump compat for Documenter to 1 for package test, (keep existing compat) (#74) (@github-actions[bot])
• Bump actions/checkout from 3 to 4 (#75) (@dependabot[bot])
• allow v0.6 of Trixi.jl (#78) (@ranocha)