devel/eric6: update to 18.12

• switch to Qt5 as default (Qt4 is depreciated) [1]
• change log:
  • Editor: changed the 'Regexp' search option to use QScintilla's POSIX mode, where ( and ) are used for tagging (instead of \( and \) )
  • LogViewer: added the capability to search for a regular expression
  • Project Forms Browser: added support for the --resource-suffix= and --import-from= options of pyuic (the PyQt forms compiler)
  • Shell, ShellWindow:
    • added the capability to search for a regular expression with QScintilla's POSIX mode
    • changed the start menu to give a list of defined environments
    • added capability to start the shell for the environment defined by the open project
  • Translator: added a button to open the Translator configuration page
  • VirtualEnv Manager: extended the environment definition by a flag indicating a Conda environment and a string to be prepended to the PATH environment variable

[1] Pre-commit hook incorrectly detects trivial change to FLAVOR as adding
FLAVOR to port

Approved by: portmgr (implicit [1])