Log Message:
tex-tcolorbox{,-doc}: update to 6.2.0

6.1.0
### Added
- New option `redirectlowerto`

### Changed
- Added braces to protect square brackets, mostly for key values
- Internal `\__tcobox_include_graphics:nn` refactored
- `blend into` now also adapts `list type` accordingly,
  e.g. `blend into=figures` now sets `list type=figure`
- `every box`, `every box on layer <n>`, and `every box on higher layers`
  may contain `capture` mode settings now

### Fixed
- With parbox=false, `\par` was ignored in a `tcolorbox` that starts a list
- `varwidth upper` ignored horizontal alignment of upper part

6.2.0
### Added
- New convenience options for box content additions
    - Option `environment upper`
    - Option `environment upper args`
    - Option `environment lower`
    - Option `environment lower args`
    - Option `environment title`
    - Option `environment title args`
- Library `hooks`:
    - Option `environment upper app`
    - Option `environment upper args app`
    - Option `environment lower app`
    - Option `environment lower args app`
    - Option `environment title app`
    - Option `environment title args app`
    - Option `environment upper pre`
    - Option `environment upper args pre`
    - Option `environment lower pre`
    - Option `environment lower args pre`
    - Option `environment title pre`
    - Option `environment title args pre`
- Library `documentation`:
    - Option `index key formatter`
    - Option `index keys formatter`
    - Root (`/`) of a documented key made configurable
        - Option `doc key prefix`

### Changed
- Minor implementation change to `redirectlowerto`
- `pgfkeys` mentioned in the documentation
- Distinct `savelowerto`/`redirectlowerto` file names inside the documentation
- Updated documentation and warnings for the interaction between `saveto`
    and `savelowerto`(issue #249)
- Improved some `\sarg` examples in the documentation
- Small typos in the documentation
- Recording macros rewritten in expl3 code
- Usage of expl3 scratch variables like `\l_tmpa_tl` replaced by package
  variables like `\l__tcobox_tmpa_tl`
- Library `documentation`:
    - Expl3 arg-spec of internal macro corrected
    - `\tcbmakedocSubKey` and `\tcbmakedocSubKeys` take options now
- Library `external`: package loading of `pdftexcmds` and `shellesc` removed.
    Expl3 functions are used as drop-in replacements
- Libraries `listings`, `listingsutf8`, and `minted`:
    package loading of `pdftexcmds` and `shellesc` removed
- Needed LaTeX version updated to 2021-11-15

### Removed
- Loading of the `xparse` library dropped inside the `documentation`
  library since all needed features are part of the LaTeX format now

### Fixed
- Several documentation typos and minor improvements
- Extra top space if `parbox=false` and tcolorbox starts with a list