Challenge 2: A task_tracker Cargo.toml — Possible Solution
====================================================================

[package]
name = "task_tracker"
version = "0.1.0"
edition = "2021"

[dependencies]
serde = "1.0"
clap = "4.0"

WHY THIS WORKS AS AN ANSWER
------------------------------
The [package] section matches this chapter's own template exactly:
name, version, and edition are the three required/conventional fields
identifying the crate itself. Since task_tracker is described as a
binary crate (not a library), this Cargo.toml alone, alongside a
src/main.rs, is enough to build a runnable program.

The [dependencies] section lists both required crates using the
default caret version requirement (an unadorned "1.0" or "4.0" is
shorthand for "^1.0"/"^4.0") — allowing any compatible 1.x version of
serde and any compatible 4.x version of clap, per this chapter's own
explanation of Cargo's default versioning behavior.

WHAT Cargo.lock ADDS ON TOP OF THIS: once the project is actually
built, Cargo resolves serde "1.0" and clap "4.0" to ONE SPECIFIC,
exact version of each (e.g. serde 1.0.197, clap 4.5.4) — including
every TRANSITIVE dependency those crates themselves pull in, each also
pinned to an exact version — and records the complete resulting
dependency graph in Cargo.lock. This guarantees that building the
project again later, or on a different machine, resolves to the
EXACT same versions every time, rather than potentially picking up a
newer compatible release that happened to be published since the last
build — precisely the reproducible-builds guarantee this chapter
compared directly to npm's package-lock.json.