Add decade 2020-2029 to copyright years in Checklics

FWIW, I just wanted to know if the tests in module 'build' would still
pass. They did not find copyrights for more recent years, so I added
them here.

But I am still unsure, if we need these tests at all. Obviously, they
were not running during CI builds, i.e. they seem to be non-essential.
But chances are, they were forgotten to be added to the suite.

BTW, running the tests in module 'build' with '-Drun.build.tests=true'
is failing, too, because some old JDK classes looked up there no longer
exist in more recent JDKs.

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>

build/src/main/java/org/aspectj/internal/tools/ant/taskdefs/Checklics.java

@@ -332,10 +332,12 @@ public class Checklics extends MatchingTask {
 	public static class License {
 		/** acceptable years for copyright prefix to company - append " " */
 		static final String[] YEARS = // remove older after license xfer?
-				new String[] {
-					"2002 ", "2003 ", "2004 ", "2005", "2006", "2007", "2008", "2009", "2010", "2011",
-					"2012", "2013", "2014", "2015", "2016", "2017", "2018", "2019", "2020", "2021",
-					"2001 ", "2000 ", "1999 " };
+			new String[] {
+				"1999",
+				"2000", "2001", "2002", "2003", "2004", "2005", "2006", "2007", "2008", "2009",
+				"2010", "2011", "2012", "2013", "2014", "2015", "2016", "2017", "2018", "2019",
+				"2020", "2021", "2022", "2023", "2024", "2025", "2026", "2027", "2028", "2029"
+			};
 		public final String tag;
 		public final String license;
 		private final String[] copyright;