Update to Android Gradle Plugin 4.0.0 + some other small dependency updates

Author: Rolf-Smit

gradle/dependencies.gradle

@@ -3,13 +3,13 @@ ext {
             minSdk    : 19,
             targetSdk : 29,
             compileSdk: 29,
-            kotlin    : "1.3.61"
+            kotlin    : "1.3.72"
     ]
     projectDependency = [
 
             // Gradle Plugins
             kotlinPlugin       : "org.jetbrains.kotlin:kotlin-gradle-plugin:${projectVersion.kotlin}",
-            androidGradlePlugin: "com.android.tools.build:gradle:3.6.1",
+            androidGradlePlugin: "com.android.tools.build:gradle:4.0.0",
 
             // Dependencies
             kotlinStdlibJdk7   : "org.jetbrains.kotlin:kotlin-stdlib-jdk7:${projectVersion.kotlin}",

plugin/src/test/kotlin/org/neotech/plugin/rootcoverage/IntegrationTest.kt

@@ -60,7 +60,7 @@ class IntegrationTest(
 
             val testFixtures = File("src/test/test-fixtures").listFiles()?.filter { it.isDirectory }
                     ?: error("Could not list test fixture directories")
-            val gradleVersions = arrayOf("5.6.4", "6.1.1", "6.2.1")
+            val gradleVersions = arrayOf("6.1.1", "6.2.1", "6.5")
             return testFixtures.flatMap { file ->
                 gradleVersions.map { gradleVersion ->
                     arrayOf("${file.name}-$gradleVersion", file, gradleVersion)