Update checkstyle toolVersion

Author: AustinShalit

build.gradle

@@ -32,10 +32,10 @@ allprojects {
     checkstyle {
         configFile = file("${project.rootDir}/google_checks.xml")
         reportsDir = file("${project.rootDir}/build/reports/checkstyle/")
+        toolVersion = '6.14'
     }
 
     dependencies {
-        compile checkstyle('com.puppycrawl.tools:checkstyle:6.14')
         testCompile group: 'net.jodah', name: 'concurrentunit', version: '0.4.2'
         testCompile group: 'org.hamcrest', name: 'hamcrest-all', version: '1.3'
         testCompile group: 'junit', name: 'junit', version: '4.12'