Include fewer deps (#3489)

Update chrono, and include fewer deps

Somewhere in the process of moving TaskChampion back to its own repo,
Taskwarrior's `Cargo.toml` ended up containing all of its dependencies,
unnecessarily.

This included an old version of `chrono` (addressed in
https://github.com/GothenburgBitFactory/taskchampion/pull/399). Removing
the old version requirement from `Cargo.toml` results in using a newer
version, addressing a (benign) security vulnerability.

xtask/Cargo.toml

@@ -4,6 +4,6 @@ version = "0.4.1"
 edition = "2021"
 
 [dependencies]
-anyhow = "1.0"
+anyhow.workspace = true
 taskchampion-lib = { path = "../src/tc/lib" }
-regex = "^1.10.2"
+regex.workspace = true