Bug fix #589. Workaround for line chart fill color

[tiagomalheiro]

See #589

This is:

- [x] a bugfix
- [ ] a new feature

Checklist:

• Changes are covered by unit tests
• Code style is respected
• Commit message explains why the change is made (see https://github.com/erlang/otp/wiki/Writing-good-commit-messages)
• CHANGELOG.md contains a short summary of the change
• Documentation is updated as necessary

Why this change is needed?

When the fill color property of DataSeries.plotLabel using a DataSeriesValues on a line chart is set, the XLSX file written is corrupted, and MSExcel2016 removes the drawing1.xml if forced open.
This problem was already documented on issue #589 along with a possible solution. So all credits go to @madrussa. I am only submitting the PR.
Used the sample file 33_Chart_create_line to test it and modified it only to include fill color:

// Set the Labels for each data series we want to plot
//     Datatype
//     Cell reference for data
//     Format Code
//     Number of datapoints in series
//     Data values
//     Data Marker
//     Fill Color
$dataSeriesLabels = [
    new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_STRING, 'Worksheet!$B$1', null, 1, [], null, '98B954'), // 2010
    new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_STRING, 'Worksheet!$C$1', null, 1, [], null, 'BE4B48'), // 2011
    new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_STRING, 'Worksheet!$D$1', null, 1, [], null, '4A7EBB'), // 2012
];

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs.
If this is still an issue for you, please try to help by debugging it further and sharing your results.
Thank you for your contributions.

[PowerKiKi]

Thank you for your patience.