itext 7.2 upgrade for jasperreports-pdf-lib7

Since JasperReport 6.17.0, a separate JasperReport plugin was created for using latest iText 7 as PDF exporter

It was made compatible for iText 7.1.x

iText 7.2.x introduced some breaking changes due to package rename, which made our custom applications cannot be upgraded to latest iText 7.2

I made a PR here for those who are interested

https://github.com/Jaspersoft/jasperreports-pdf-lib7/pull/5

Would project maintainer of jasperreports-pdf-lib7 please review the change and prepare for the release

Thanks