update maven pom setting to YaCy version 1.921

java 1.8 and solr 6.6

pom.xml

@@ -4,7 +4,7 @@
 
     <groupId>net.yacy</groupId>
     <artifactId>yacycore</artifactId>
-    <version>1.92</version>
+    <version>1.921</version>
     <packaging>jar</packaging>
     <description>YaCy - a Peer to Peer Web Search Engine</description>
     <name>YaCy Search Server</name>
@@ -31,10 +31,10 @@
 
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <maven.compiler.source>1.7</maven.compiler.source>
-        <maven.compiler.target>1.7</maven.compiler.target>
+        <maven.compiler.source>1.8</maven.compiler.source>
+        <maven.compiler.target>1.8</maven.compiler.target>
         <!-- the Solr version used in dependency section for all related dependencies -->
-        <solr.version>5.5.4</solr.version> 
+        <solr.version>6.6.0</solr.version> 
         <!-- the Jetty version used in dependency section for all related dependencies -->
         <jetty.version>9.2.21.v20170120</jetty.version>