Incorrect identification of sequences of digits with one or more leading zero as Numbers

[stephanbuys]

The YAML 1.2 Spec does not allow Numbers to start with a 0 unless it is used to identify different kinds of number formats (such as Octal, etc).
See

serde-yaml/src/de.rs

Line 523 in c49f115

if v.starts_with("0x") || v.starts_with("+0x") {

A digit sequence with leading zeros that isn't one of these types (and identified as such) should instead be interpreted as a String, see: https://yaml.org/spec/1.2/spec.html#id2761292

I'm happy to contribute a PR if wanted.

Examples:

string: 00082
integer: 82