requirements: Update Pygments to 2.1.

- Added lexers:
    - Emacs Lisp
    - Arduino
    - Modula-2 with multi-dialect support
    - Fortran fixed format
    - Archetype Definition language
    - Terraform
    - Jcl, Easytrieve
    - ParaSail
    - Boogie
    - Turtle
    - Fish Shell
    - Roboconf
    - Test Anything Protocol
    - Shen
    - Component Pascal
    - SuperCollider
    - Shell consoles (Tcsh, PowerShell, MSDOS)
    - Elm and J
    - Crmsh
    - Praat
    - CSound
    - Ezhil
    - Thrift
    - QVT Operational
    - Hexdump
    - CAmkES Configuration
    - Added styles:
    - Lovelace
    - Algol and Algol-nu
- Added formatters:
    - IRC
- True color (24-bit) terminal ANSI sequences (formatter alias: “16m”)
- New “filename” option for HTML formatter.
- Improved performance of the HTML formatter for long lines.
- Updated autopygmentize script.
- Fixed style inheritance for non-standard token types in HTML output.
- Added support for async/await to Python 3 lexer.
- Rewrote linenos option for TerminalFormatter (it’s better, but slightly
  different output than before).
- Javascript lexer now supports most of ES6.
- Cocoa builtins updated for iOS 8.1.
- Combined BashSessionLexer and ShellSessionLexer, new version should support
  the prompt styles of either.
- Added option to pygmentize to show a full traceback on exceptions.
- Fixed incomplete output on Windows and Python 3 (e.g. when using iPython
  Notebook).
- Allowed more traceback styles in Python console lexer.
- Added decorators to TypeScript.
- Fix highlighting of certain IRC logs formats.

requirements.txt

@@ -1,6 +1,6 @@
 Jinja2==2.8.0
 MarkupSafe==0.23
-Pygments==2.0.2
+Pygments==2.1
 pyPEG2==2.15.2
 PyYAML==3.11
 colorama==0.3.6