math/py-pcodec: Add py-pcodec 0.3.4

Pcodec (or Pco) losslessly compresses and decompresses numerical sequences with
high compression ratio and moderately fast speed.

Use cases include:

• columnar data
• long-term time series data
• serving numerical data to web clients
• low-bandwidth communication

Data types: u16, u32, u64, i16, i32, i64, f16, f32, f64