Log Message:
blosc: updated to 1.19.0

Changes from 1.18.1 to 1.19.0
=============================

- The length of automatic blocksizes for fast codecs (lz4, blosclz) has
  been incremented quite a bit (up to 256 KB) for better compression ratios.
  The performance in modern CPUs (with at least 256 KB in L2 cache) should
  be better too (for older CPUs the performance should stay roughly the same).

- Continuous integration has been migrated to GitHub actions and much
  more scenarios are tested (specially linking with external codecs).
  Also, a new OSS-Fuzz workflow has been added for increased detection
  of possible vulnerabilities.  Thanks to Nathan Moinvaziri.

- blosclz codec updated to 2.1.0.  Expect better compression ratios and
  performance in a wider variety of scenarios.

- `blosc_decompress_unsafe()`, `blosc_decompress_ctx_unsafe()` and
  `blosc_getitem_unsafe()` have been removed because they are dangerous
  and after latest improvements, they should not be used in production.

- zstd codec updated to 1.4.5.

- Conan packaging has been deprecated (from now on, we should try
  to focus on supporting wheels only).