jiff::fmt::strtime::parse panics on certain malformed inputs due to integer overflow

[apasel422]

Example code:

 _ = jiff::fmt::strtime::parse([37, 94, 53, 48, 67, 37], [50, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 35, 48, 48, 55, 55, 41, 40, 41]);

Output:

panicked at src/fmt/strtime/parse.rs:869:45:
called `Option::unwrap()` on a `None` value
stack backtrace:
   0: __rustc::rust_begin_unwind
             at /rustc/1159e78c4747b02ef996e55082b704c09b970588/library/std/src/panicking.rs:697:5
   1: core::panicking::panic_fmt
             at /rustc/1159e78c4747b02ef996e55082b704c09b970588/library/core/src/panicking.rs:75:14
   2: core::panicking::panic
             at /rustc/1159e78c4747b02ef996e55082b704c09b970588/library/core/src/panicking.rs:145:5
   3: core::option::unwrap_failed
             at /rustc/1159e78c4747b02ef996e55082b704c09b970588/library/core/src/option.rs:2130:5
   4: core::option::Option<T>::unwrap
             at /rustc/1159e78c4747b02ef996e55082b704c09b970588/library/core/src/option.rs:1009:21
   5: jiff::fmt::strtime::parse::Parser::parse_century
             at ./src/fmt/strtime/parse.rs:869:45
   6: jiff::fmt::strtime::parse::Parser::parse
             at ./src/fmt/strtime/parse.rs:56:30
   7: jiff::fmt::strtime::BrokenDownTime::parse_mono
             at ./src/fmt/strtime/mod.rs:941:11
   8: jiff::fmt::strtime::BrokenDownTime::parse
             at ./src/fmt/strtime/mod.rs:934:9
   9: jiff::fmt::strtime::parse
             at ./src/fmt/strtime/mod.rs:355:5

century=2000000000000000000 prior to the checked multiplication by 100.