Update to gradle 4.9 (#1193)

4.9 will be needed for some things being added to a few of our plugins. It adds the new lazy configuration tasks which help a good amount in some cases.

build.gradle

@@ -6,7 +6,7 @@ plugins {
     id 'edu.wpi.first.GradleJni' version '0.2.2'
     id 'edu.wpi.first.GradleVsCode' version '0.3.0'
     id 'idea'
-    id 'com.gradle.build-scan' version '1.13.1'
+    id 'com.gradle.build-scan' version '1.15.1'
 }
 
 repositories {
@@ -92,5 +92,5 @@ subprojects {
 }
 
 wrapper {
-    gradleVersion = '4.8.1'
+    gradleVersion = '4.9'
 }

gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.8.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.9-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists