python3-pygments: upgrade v2.7.2 -> v2.7.3

Upstream release notes:
"""
 * 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
"""

Signed-off-by: Tim Orling <timothy.t.orling@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>