update dependencies and adapt to breaking changes and material 3

update dependencies and adapt to breaking changes and material 3

Adapt the theme color variables to the new names of Material Design 3
[0], and the text button styles to the styleFrom property changes
[1].

[0]: https://docs.flutter.dev/release/breaking-changes/material-3-migration
[1]: https://docs.flutter.dev/release/breaking-changes/3-16-deprecations#button-stylefrom-properties

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>