feat: add command to print task dependency tree

[roele]

First rough draft to visualize task depencies (#1272).

Changes

• moved Deps to tasks/deps.rs and made crate/struct public
• added new task command deps [--dot] [TASKS]...
• uses crate ptree to render a tree directly from a petgraph::Graph
• uses crate petgraph to render a DOT representation which can be piped via | dot -Tpng > ./graph.png

Open issues

• [tree] ptree does not seem to allow customization of output and simply uses fmt::Display which currently has the format [TASK] CMD...
• [tree] sub-tasks seem to be in wrong order
• [dot] only renders nodes with incoming edges

Looking forward to some comments, as a Rust newby i feel there is a lot of room for improvement in that first rough draft.

[jdx]

moved Deps to tasks/deps.rs and made crate/struct public

I wonder if we should reconsider the term depends used on task definitions to also be "deps".

[tree] ptree does not seem to allow customization of output and simply uses fmt::Display which currently has the format [TASK] CMD...

we could fork it (no update in 2 years), or change the way we use fmt::Display in other places, or you could use a different data structure maybe

I think it's definitely on the right track though, mostly the fmt::Display issue makes it not look great but I think when that is fixed it will look incredible. DIdn't test the dot stuff, I'll wait a bit till you get the last thing fixed.

Definitely a good start though, especially as a rust newbie. That petgraph stuff definitely isn't easy to work with.

[roele]

• moved Deps to task.rs
• removed crate ptree and re-implemented rendering of the Graph as tree

TODO

• move generic tree rendition structs and code to ui/tree.rs
• clean up and simplify code where possible
• revisit DOT format because of missing tasks without edges
• add tests

[roele]

I revisited the DOT format export but it seems there is no way to show tasks which do not have any edges (dependencies). Also the export has almost no configuration options.

Also EndBug/add-and-commit@v9 fails the unit test step currently and might require a smarter condition to prevent trying to update my repository to which it has no access to.

[jdx]

nice work!