For #15644: update Android Gradle Plugin version.

This ensures our custom lint rules are running on the command line.

build.gradle

@@ -29,7 +29,7 @@ buildscript {
         } else {
             google() {
                 content {
-                    // Improve performance: only check google maven for mozilla deps.
+                    // Improve performance: only check google maven for google deps.
                     includeGroupByRegex RepoMatching.androidx
                     includeGroupByRegex RepoMatching.comGoogleAndroid
                     includeGroupByRegex RepoMatching.comGoogleFirebase
@@ -102,7 +102,7 @@ allprojects {
         } else {
             google() {
                 content {
-                    // Improve performance: only check google maven for mozilla deps.
+                    // Improve performance: only check google maven for google deps.
                     includeGroupByRegex RepoMatching.androidx
                     includeGroupByRegex RepoMatching.comGoogleAndroid
                     includeGroupByRegex RepoMatching.comGoogleFirebase

buildSrc/src/main/java/Dependencies.kt

@@ -5,7 +5,12 @@
 object Versions {
     const val kotlin = "1.3.72"
     const val coroutines = "1.3.3"
-    const val android_gradle_plugin = "3.5.0"
+
+    // These versions are linked: lint should be X+23.Y.Z of gradle_plugin version, according to:
+    // https://github.com/alexjlockwood/android-lint-checks-demo/blob/0245fc027463137b1b4afb97c5295d60dce998b6/dependencies.gradle#L3
+    const val android_gradle_plugin = "3.6.4"
+    const val android_lint_api = "26.6.4"
+
     const val sentry = "1.7.10"
     const val leakcanary = "2.4"
     const val leanplum = "5.4.0"

mozilla-lint-rules/build.gradle

@@ -9,9 +9,9 @@ targetCompatibility = JavaVersion.VERSION_1_8
 sourceCompatibility = JavaVersion.VERSION_1_8
 
 dependencies {
-    compileOnly "org.jetbrains.kotlin:kotlin-stdlib:1.3.61"
-    compileOnly "com.android.tools.lint:lint-api:26.6.1"
-    compileOnly "com.android.tools.lint:lint-checks:26.6.1"
+    compileOnly "org.jetbrains.kotlin:kotlin-stdlib:${Versions.kotlin}"
+    compileOnly "com.android.tools.lint:lint-api:${Versions.android_lint_api}"
+    compileOnly "com.android.tools.lint:lint-checks:${Versions.android_lint_api}"
 }
 
 jar {