Windows CPU frequency does not refresh

Describe the bug When retrieving the frequency in windows, it only retrieves it once and then never again refreshes it, even if the refresh flag is used. Looking through the code, there is a boolean that is used to retrieve the frequency just once (not sure the reason for this):

pub fn get_frequencies(&mut self) {
    if self.got_cpu_frequency {
        return;
    }
    let frequencies = get_frequencies(self.cpus.len());

    for (cpu, frequency) in self.cpus.iter_mut().zip(frequencies) {
        cpu.inner.set_frequency(frequency);
    }
    self.got_cpu_frequency = true;
}

I can do a PR and fix this if it's a bug.

To Reproduce

fn main() {
    let mut sys = sysinfo::System::new_all();
    loop {
        sys.refresh_cpu_frequency();
        dbg!(sys
            .cpus()
            .iter()
            .map(|el| el.frequency())
            .collect::<Vec<_>>());
        std::thread::sleep(std::time::Duration::from_secs(1));
    }
}

GuillaumeGomez / sysinfo

Windows CPU frequency does not refresh #1390