Serving Pages to the Web in CH2 - 2nd ed

[Slyfox88]

Running the code around page 18 gives me the following error:

error[E0277]: cannot subtract `chrono::Duration` from `Tm`
cookie.set_expires(time::now() - Duration::days(365));
| ^ no implementation for `Tm - chrono::Duration`
|
= help: the trait `Sub<chrono::Duration>` is not implemented for `Tm`
= help: the following other types implement trait `Sub<Rhs>`:
<Tm as Sub<time::Duration>>
<Tm as Sub>

The compiler doesn't even reach my code, so it must be an issue with dependencies.
Based on this Reddit post, other people are getting the same error:
https://www.reddit.com/r/rust/comments/17djgjd/working_through_programming_rust_2nd_edition_got/

Adding this dependency fixes the issue:
chrono = { version = "= 0.4.29" }