Log Message:
tex-tcolorbox{,-doc}: update to 4.42

4.42
- due to several problems with the color algorithm introduced with
  version 4.32, essentially reversion to the proven pre 4.32 method.
  * support of luacolor persists (since 4.32)
  * color stacks (by pdfcol) are not mandatory any more,
    but are optional now with 'use color stack'. Note that effects
    of whatsits on the vertical space have to be expected.

4.41
- bug fix: color bleeding for xelatex and breakable boxes (since 4.32)

4.40
- bug fix: 'IfBooleanT', 'IfBooleanF'
- bug fix: 'widget' set 'toprule at break' and needed the breakable library
- (bug) fix: style 'marker' set 'breakable' and needed the breakable library
- 'capture=hbox' applies '\@parboxrestore' now to allow e.g. hbox style
    listings inside indented environments like itemize
- support 'hbox' for 'minted' listings
- New default vertical space options
        'before skip balanced', 'after skip balanced', 'beforeafter skip
  balanced'
  NOTE: These options replace the current default options
        'parskip', 'noparskip', 'autoparskip'
  WARNING: Old documents may need adapted manual page breaks where used.
           Otherwise: Use \tcbsetforeverylayer{autoparskip}
           to restore the old behavior!
- 'before skip' and 'before skip balanced' do not insert glue now, if
  the tcolorbox is the first element in a minipage (or sourrounding tcolorbox)

4.32
- documentation typo corrections and enhancements
- bug fix: 'index format=doc' caused redefinition of '\_'
  among other errors.
- bug fix: 'valign=scale*' was erroneous.
- enhancement: color stack support for breakable boxes (pdflatex and
  lualatex) to let colors survive a break to the next partial box.
- library 'xparse':
  * new options: 'IfNoValueT', 'IfNoValueF', 'IfValueT', 'IfValueF',
      'IfBooleanT', 'IfBooleanF'

4.31
- bug fix: \tcbincludepdf did not work for lualatex
- bug fix: Several tests had a missing \relax
- bug fix: Breakable tcolorbox may overlap with following the
  text
- bug fix: 'space to' did not result in a stable value
- Internal change: all 'code 2 args' replaced by 'code n args={2}'
- documentation typo corrections
- library 'documentation':
  * indention of <environment content> changed to \ttfamily