Update to Tycho 1.6.0

Not many changes, but might lead to shorter build times.

Change-Id: I5d629e49e8bbdef7a5b116d4f28cdbf8a8528cf0
Signed-off-by: Michael Keppler <Michael.Keppler@gmx.de>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit.packaging/pom.xml

@@ -22,7 +22,7 @@
   <name>JGit Tycho Parent</name>
 
   <properties>
-    <tycho-version>1.5.1</tycho-version>
+    <tycho-version>1.6.0</tycho-version>
     <tycho-extras-version>${tycho-version}</tycho-extras-version>
     <target-platform>jgit-4.6</target-platform>
   </properties>

pom.xml

@@ -169,7 +169,7 @@
     <slf4j-version>1.7.2</slf4j-version>
     <log4j-version>1.2.15</log4j-version>
     <maven-javadoc-plugin-version>3.1.1</maven-javadoc-plugin-version>
-    <tycho-extras-version>1.5.1</tycho-extras-version>
+    <tycho-extras-version>1.6.0</tycho-extras-version>
     <gson-version>2.8.2</gson-version>
     <bouncycastle-version>1.64</bouncycastle-version>
     <spotbugs-maven-plugin-version>3.1.12.2</spotbugs-maven-plugin-version>