Upgrade to Gradle 6.7

Closes gh-23754

gradle/wrapper/gradle-wrapper.properties

 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.6.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.7-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/asciidoc/packaging.adoc

@@ -119,7 +119,7 @@ include::../gradle/packaging/spring-boot-dsl-main-class.gradle[tags=main-class]
 include::../gradle/packaging/spring-boot-dsl-main-class.gradle.kts[tags=main-class]
 ----
 
-If the {application-plugin}[`application` plugin] has been applied its `mainClassName` project property must be configured and can be used for the same purpose:
+If the {application-plugin}[`application` plugin] has been applied its `mainClass` property must be configured and can be used for the same purpose:
 
 [source,groovy,indent=0,subs="verbatim,attributes",role="primary"]
 .Groovy

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/asciidoc/running.adoc

@@ -56,7 +56,7 @@ include::../gradle/running/boot-run-disable-optimized-launch.gradle[tags=launch]
 include::../gradle/running/boot-run-disable-optimized-launch.gradle.kts[tags=launch]
 ----
 
-If the {application-plugin}[`application` plugin] has been applied, its `mainClassName` property must be configured and can be used for the same purpose:
+If the {application-plugin}[`application` plugin] has been applied, its `mainClass` property must be configured and can be used for the same purpose:
 
 [source,groovy,indent=0,subs="verbatim,attributes",role="primary"]
 .Groovy

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/gradle/packaging/application-plugin-main-class.gradle

@@ -5,5 +5,7 @@ plugins {
 }
 
 // tag::main-class[]
-mainClassName = 'com.example.ExampleApplication'
+application {
+	mainClass = 'com.example.ExampleApplication'
+}
 // end::main-class[]

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/gradle/packaging/application-plugin-main-class.gradle.kts

@@ -6,6 +6,6 @@ plugins {
 
 // tag::main-class[]
 application {
-	mainClassName = "com.example.ExampleApplication"
+	mainClass.set("com.example.ExampleApplication")
 }
 // end::main-class[]

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/gradle/running/application-plugin-main-class-name.gradle

@@ -6,7 +6,7 @@ plugins {
 
 // tag::main-class[]
 application {
-	mainClassName = 'com.example.ExampleApplication'
+	mainClass = 'com.example.ExampleApplication'
 }
 // end::main-class[]
 

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/gradle/running/application-plugin-main-class-name.gradle.kts

@@ -8,7 +8,7 @@ plugins {
 
 // tag::main-class[]
 application {
-	mainClassName = "com.example.ExampleApplication"
+	mainClass.set("com.example.ExampleApplication")
 }
 // end::main-class[]
 

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/junit/GradleCompatibilityExtension.java

@@ -45,10 +45,10 @@ public final class GradleCompatibilityExtension implements TestTemplateInvocatio
 		JavaVersion javaVersion = JavaVersion.current();
 		if (javaVersion.isCompatibleWith(JavaVersion.VERSION_14)
 				|| javaVersion.isCompatibleWith(JavaVersion.VERSION_13)) {
-			GRADLE_VERSIONS = Arrays.asList("6.3", "6.4.1", "6.5.1", "default", "6.7-rc-1");
+			GRADLE_VERSIONS = Arrays.asList("6.3", "6.4.1", "6.5.1", "6.6.1", "default");
 		}
 		else {
-			GRADLE_VERSIONS = Arrays.asList("5.6.4", "6.3", "6.4.1", "6.5.1", "default", "6.7-rc-1");
+			GRADLE_VERSIONS = Arrays.asList("5.6.4", "6.3", "6.4.1", "6.5.1", "6.6.1", "default");
 		}
 	}