v4.2.0

• #3811 add support for container queries (@puckowski)
• #3761 fix faulty source map generation with variables in selectors, fixes #3567 (@pgoldberg)
• #3700 parsing variables fail when there is no trailing semicolon (@b-kelly)
• #3719 modify this pointer so that it is not empty. (@lumburr)
• #3649 fixes #2991 empty @media queries generated when compiling less file with (reference) to bootstrap (@MoonCoral)