Update changelog with recent PR merges, and fix #38

[MathiasKoch]

This will update the changelog to reflect the merges from:

• Add to_slice serialization function #36 / Slice serialization #27
• Newtype, variants and unit #25
• Return the number of bytes used in the deserialization process #26
• Handle whitespace before sequence in deserialization #32
• Correctly handle escaped strings when parsing json strings. Fixes #30 & #31 #34

And fixes #38 to correct the repository link in Cargo.toml

[MathiasKoch]

We just need to land #25 before we can merge this.

[MathiasKoch]

@eldruin
Think we are ready for a release PR after this has passed CI

[eldruin]

Indeed. Looks good to me. Thank you @MathiasKoch!