lab

• bump pretty_assertions (dev dependency) crate from version 0.6 to 0.7
• bump approx (dev dependency) crate from version 0.3 to 0.5

• bump rand crate from version 0.5 to 0.8
• fix a potential edge case error. Per @mina86:

  the rgb_to_xyz_map function uses threshold equal 10. This is fine if the argument is an integer in 0–255 range (255 * 0.0404 = 10.302) which the function was originally designed to handle. However, it has since been changed to accept floating point numbers in said range. As a result, if a colour component is, say, 10.1, the function will use the wrong gamma expansion formula.

• add LCh data struct - @mina86

• No code changes
• Includes Readme and license files in published crate

• Fix a bug in AVX2 path of labs_to_rgb_bytes

• Speed up AVX2 code path, primarily by bringing in an AVX2 impl of powf, log, and exp
• Remove simd as a public module
• rgbs_to_labs and labs_to_rgbs: uses AVX2 code paths when compiled on a target that supports it
• rgb_bytes_to_labs and labs_to_rgb_bytes: works with RGB triples in a flat &[u8] instead of &[[u8; 3]]

• add convenience methods for converting slices of labs/rgbs
• add experimental simd module with functions using avx and sse4.1 operations

• More accurate FP calculations - @mina86

• Update rand crate from version 0.3 to 0.5

Current version when CHANGELOG.md was created.