Update copyright notes year

DEVSIX-2562

Author: yulian-gaponenko

itext/itext.font-asian/iText Asian Font.nuspec

@@ -13,7 +13,7 @@
     <description>iText Asian fonts for use in conjunction with iText 7, an open source PDF library</description>
     <summary></summary>
     <releaseNotes>http://itextpdf.com/itext7release</releaseNotes>
-    <copyright>Copyright (c) 1998-2018 iText Group NV</copyright>
+    <copyright>Copyright (c) 1998-2019 iText Group NV</copyright>
     <language>en-US</language>
     <tags>itext itext7 itextsharp c# .net csharp pdf asian font-asian</tags>
     <dependencies>

itext/itext.hyph/iText Hyph.nuspec

@@ -13,7 +13,7 @@
     <description>XML files that can be used for hyphenation with iText 7, an open source PDF library</description>
     <summary></summary>
     <releaseNotes>http://itextpdf.com/itext7release</releaseNotes>
-    <copyright>Copyright (c) 1998-2018 iText Group NV</copyright>
+    <copyright>Copyright (c) 1998-2019 iText Group NV</copyright>
     <language>en-US</language>
     <tags>itext itext7 itextsharp c# .net csharp pdf hyphenation hyph</tags>
     <dependencies>

itext/itext.pdftest/itext7-pdftest.nuspec

@@ -13,7 +13,7 @@
     <description>A special module for test purposes</description>
     <summary></summary>
     <releaseNotes>http://itextpdf.com/itext7release</releaseNotes>
-    <copyright>Copyright (c) 1998-2018 iText Group NV</copyright>
+    <copyright>Copyright (c) 1998-2019 iText Group NV</copyright>
     <language>en-US</language>
     <tags>itext itext7 itextsharp c# .net csharp pdf tests</tags>
     <dependencies>

itext7.nuspec

@@ -13,7 +13,7 @@
     <description>iText 7 represents the next level of SDKs for developers that want to take advantage of the benefits PDF can bring. Equipped with a better document engine, high- and low-level programming capabilities and the ability to create, edit and enhance PDF documents, iText 7 can be a boon to nearly every workflow. iText 7 allows you to build custom PDF scenarios for web, mobile, desktop or cloud apps in Java and .NET.</description>
     <summary>iText for .NET is a port of the iText open source java library for PDF generation written entirely in C# for the .NET platform.</summary>
     <releaseNotes>http://itextpdf.com/itext7release</releaseNotes>
-    <copyright>Copyright (c) 1998-2018 iText Group NV</copyright>
+    <copyright>Copyright (c) 1998-2019 iText Group NV</copyright>
     <language>en-US</language>
     <tags>itext itext7 itextsharp c# .net csharp pdf</tags>
     <dependencies>