v0.3.16

Trixi2Vtk v0.3.16

Diff since v0.3.15

Merged pull requests:

• Bump julia-actions/setup-julia from 1 to 2 (#93) (@dependabot[bot])
• Bump julia-actions/cache from 1 to 2 (#94) (@dependabot[bot])
• allow new nine-digit file name format of Trixi.jl v0.8 (#96) (@ranocha)