Update pygments to 2.3.0

[pyup-bot]

This PR updates pygments from 2.1 to 2.3.0.

Changelog

2.3.0

-------------
(released Nov 25, 2018)

- Added lexers:

* Fennel (PR783)
* HLSL (PR675)

- Updated lexers:

* Dockerfile (PR714)

- Minimum Python versions changed to 2.7 and 3.5
- Added support for Python 3.7 generator changes (PR772)
- Fix incorrect token type in SCSS for single-quote strings (1322)
- Use `terminal256` formatter if `TERM` contains `256` (PR666)
- Fix incorrect handling of GitHub style fences in Markdown (PR741, 1389)
- Fix `%a` not being highlighted in Python3 strings (PR727)

2.2.0

-------------
(released Jan 22, 2017)

- Added lexers:

* AMPL
* TypoScript (1173)
* Varnish config (PR554)
* Clean (PR503)
* WDiff (PR513)
* Flatline (PR551)
* Silver (PR537)
* HSAIL (PR518)
* JSGF (PR546)
* NCAR command language (PR536)
* Extempore (PR530)
* Cap'n Proto (PR595)
* Whiley (PR573)
* Monte (PR592)
* Crystal (PR576)
* Snowball (PR589)
* CapDL (PR579)
* NuSMV (PR564)
* SAS, Stata (PR593)

- Added the ability to load lexer and formatter classes directly from files
with the `-x` command line option and the `lexers.load_lexer_from_file()`
and `formatters.load_formatter_from_file()` functions. (PR559)

- Added `lexers.find_lexer_class_by_name()`. (1203)

- Added new token types and lexing for magic methods and variables in Python
and PHP.

- Added a new token type for string affixes and lexing for them in Python, C++
and Postgresql lexers.

- Added a new token type for heredoc (and similar) string delimiters and
lexing for them in C++, Perl, PHP, Postgresql and Ruby lexers.

- Styles can now define colors with ANSI colors for use in the 256-color
terminal formatter. (PR531)

- Improved the CSS lexer. (1083, 1130)

- Added "Rainbow Dash" style. (PR623)

- Delay loading `pkg_resources`, which takes a long while to import. (PR690)

2.1.3

-------------
(released Mar 2, 2016)

- Fixed regression in Bash lexer (PR563)

2.1.2

-------------
(released Feb 29, 2016)

- Fixed Python 3 regression in image formatter (1215)
- Fixed regression in Bash lexer (PR562)

2.1.1

-------------
(relased Feb 14, 2016)

- Fixed Jython compatibility (1205)
- Fixed HTML formatter output with leading empty lines (1111)
- Added a mapping table for LaTeX encodings and added utf8 (1152)
- Fixed image formatter font searching on Macs (1188)
- Fixed deepcopy-ing of Token instances (1168)
- Fixed Julia string interpolation (1170)
- Fixed statefulness of HttpLexer between get_tokens calls
- Many smaller fixes to various lexers

Links

• PyPI: https://pypi.org/project/pygments
• Changelog: https://pyup.io/changelogs/pygments/
• Homepage: http://pygments.org/

[pyup-bot]

Closing this in favor of #216