MAI: rm unused from pyparsing import Upcase in dot_parser

besides being unused, it has been deprecated,
and removed in pyparsing >= 2.1.0, by svn revision 320 [1].

[1] https://sourceforge.net/p/pyparsing/code/320/

dot_parser.py

@@ -22,7 +22,7 @@
 
 from pyparsing import __version__ as pyparsing_version
 
-from pyparsing import ( nestedExpr, Literal, CaselessLiteral, Word, Upcase, OneOrMore, ZeroOrMore,
+from pyparsing import ( nestedExpr, Literal, CaselessLiteral, Word, OneOrMore, ZeroOrMore,
     Forward, NotAny, delimitedList, oneOf, Group, Optional, Combine, alphas, nums,
     restOfLine, cStyleComment, nums, alphanums, printables, empty, quotedString,
     ParseException, ParseResults, CharsNotIn, _noncomma, dblQuotedString, QuotedString, ParserElement )