v0.7.0 - added keywords from Solidity v0.7.x and v0.8.x.
v0.6.0 - new NatSpec keywords, require Python v3.3+.
v0.6 - new NatSpec keywords, require Python v3.3+.
v0.5.1 - bugfix, detect `:` as punctuation in Yul.
v0.5.0 - add Yul lexer.
v0.4.1 - port back fixes from Rouge's lexer PR.
v0.4.0 - update keywords up to those in `solc` v0.6.0.
v0.3.1 - only highlight actual "nested" keywords.
v0.3.0 - highlight NatSpec specials.
v0.2.0 - update keywords up to those in `solc` v0.4.22.
v0.1.0 - update keywords up to those in `solc` v0.4.21.
v0.0.3 - update keywords up to those in `solc` v0.4.18.
v0.0.2 - change license from MIT to BSD
v0.0.1 - initial release.