google format version update

Author: Emil-Gustafsson

build.gradle

@@ -38,6 +38,10 @@ repositories {
     mavenCentral()
 }
 
+googleJavaFormat {
+  toolVersion = '1.7'
+}
+
 dependencies {
     compile group: 'org.pcap4j', name: 'pcap4j-packetfactory-static', version:'1.7.7' //1.8.0+ requires java 9
     compile group: 'org.apache.commons', name: 'commons-lang3', version:'3.9'