Update default dependencies in aoc_template

Now includes `rayon`, `itertools` and `id_arena`, as these crates
have proven very useful when writing any kind of Rust.

2022/aoc_template/Cargo.toml

@@ -6,3 +6,6 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+rayon = "1"
+itertools = "0"
+id-arena = { version = "2", features = ["rayon"] }