Update pygments to 2.7.4

[pyup-bot]

This PR updates pygments from 2.7.1 to 2.7.4.

Changelog

2.7.4

-------------
(released January 12, 2021)

- Updated lexers:

- Apache configurations: Improve handling of malformed tags (1656)
- CSS: Add support for variables (1633, 1666)
- Crystal (1650, 1670)
- Coq (1648)
- Fortran: Add missing keywords (1635, 1665)
- Ini (1624)
- JavaScript and variants (1647 -- missing regex flags, 1651)
- Markdown (1623, 1617)
- Shell

 - Lex trailing whitespace as part of the prompt (1645)
 - Add missing ``in`` keyword (1652)
 
- SQL - Fix keywords (1668)
- Typescript: Fix incorrect punctuation handling (1510, 1511)

- Fix infinite loop in SML lexer (1625)
- Fix backtracking string regexes in JavaScript/TypeScript, Modula2
and many other lexers (1637)
- Limit recursion with nesting Ruby heredocs (1638)
- Fix a few inefficient regexes for guessing lexers
- Fix the raw token lexer handling of Unicode (1616)
- Revert a private API change in the HTML formatter (1655) -- 
please note that private APIs remain subject to change!
- Fix several exponential/cubic-complexity regexes found by
Ben Caller/Doyensec (1675)
- Fix incorrect MATLAB example (1582)

Thanks to Google's OSS-Fuzz project for finding many of these bugs.

2.7.3

-------------
(released December 6, 2020)

- Updated lexers:

* Ada (1581)
* HTML (1615, 1614)
* Java (1594, 1586)
* JavaScript (1605, 1589, 1588)
* JSON (1569 -- this is a complete rewrite)
* Lean (1601)
* LLVM (1612)
* Mason (1592)
* MySQL (1555, 1551)
* Rust (1608)
* Turtle (1590, 1553)

- Deprecated JsonBareObjectLexer, which is now identical to JsonLexer (1600)
- The ``ImgFormatter`` now calculates the exact character width, which fixes some issues with overlapping text (1213, 1611)
- Documentation fixes (1609, 1599, 1598)
- Fixed duplicated Juttle language alias (1604, 1606)
- Added support for Kotlin scripts (1587)
- Removed CSS rule which forced margin to 0

2.7.2

-------------
(released October 24, 2020)

- Updated lexers:

* Latex (1517, 1516)
* LLVM (1565)
* SPARQL (1559)

- Fix Python console/traceback lexer problems with custom exceptions without messages (1548)
- Allow loading ttc fonts on Mac/image formatter (1223)
- Improve ``analyze_text`` across a variety of lexers (1549)
- Remove CSS rule which forced the vertical padding to 0 for line numbers (1583, 1579)
- Fix ``TNTLexer`` crashing on unexpected EOL (1568, 1570)
- ``regexlint`` can be now run locally as part of ``tox`` tests (1557)
- Fix typos (1550, 1562)
- Add Python 3.9 as a supported version (1554)

Links

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

[pyup-bot]

Closing this in favor of #1580