Version information shouldn't require hand-parsing

Per https://task.ms/26741093 - `CPPWINRT_VERSION` is a string. Could it also be a four-part structure?

```c++
struct cppwinrt_version_t {
    uint16_t major;
    uint16_t minor;
    uint16_t release;
    uint16_t build;
};
constexpr cppwinrt_version_t get_cppwinrt_version() {
    return { 2, 0, 20609, 3 };
}
```