Update docs/samples to Spring Boot 4.0.0-M2

Closes gh-2186

docs/spring-authorization-server-docs.gradle

@@ -51,7 +51,7 @@ repositories {
 }
 
 dependencies {
-	implementation(platform("org.springframework.boot:spring-boot-dependencies:4.0.0-SNAPSHOT")) {
+	implementation(platform("org.springframework.boot:spring-boot-dependencies:4.0.0-M2")) {
 		exclude group: "org.springframework.security", module: "spring-security-oauth2-authorization-server"
 	}
 	implementation platform("org.springframework.security:spring-security-bom:7.0.0-M2")

samples/backend-for-spa-client/samples-backend-for-spa-client.gradle

@@ -1,5 +1,5 @@
 plugins {
-	id "org.springframework.boot" version "4.0.0-SNAPSHOT"
+	id "org.springframework.boot" version "4.0.0-M2"
 	id "io.spring.dependency-management" version "1.1.0"
 	id "java"
 }

samples/default-authorizationserver/samples-default-authorizationserver.gradle

@@ -1,5 +1,5 @@
 plugins {
-	id "org.springframework.boot" version "4.0.0-SNAPSHOT"
+	id "org.springframework.boot" version "4.0.0-M2"
 	id "io.spring.dependency-management" version "1.1.0"
 	id "java"
 }

samples/demo-authorizationserver/samples-demo-authorizationserver.gradle

@@ -1,5 +1,5 @@
 plugins {
-	id "org.springframework.boot" version "4.0.0-SNAPSHOT"
+	id "org.springframework.boot" version "4.0.0-M2"
 	id "io.spring.dependency-management" version "1.1.0"
 	id "java"
 }

samples/demo-client/samples-demo-client.gradle

@@ -1,5 +1,5 @@
 plugins {
-	id "org.springframework.boot" version "4.0.0-SNAPSHOT"
+	id "org.springframework.boot" version "4.0.0-M2"
 	id "io.spring.dependency-management" version "1.1.0"
 	id "java"
 }

samples/messages-resource/samples-messages-resource.gradle

@@ -1,5 +1,5 @@
 plugins {
-	id "org.springframework.boot" version "4.0.0-SNAPSHOT"
+	id "org.springframework.boot" version "4.0.0-M2"
 	id "io.spring.dependency-management" version "1.1.0"
 	id "java"
 }

samples/users-resource/samples-users-resource.gradle

@@ -1,5 +1,5 @@
 plugins {
-	id "org.springframework.boot" version "4.0.0-SNAPSHOT"
+	id "org.springframework.boot" version "4.0.0-M2"
 	id "io.spring.dependency-management" version "1.1.0"
 	id "java"
 }

samples/x509-certificate-generator/samples-x509-certificate-generator.gradle

@@ -1,5 +1,5 @@
 plugins {
-	id "org.springframework.boot" version "4.0.0-SNAPSHOT"
+	id "org.springframework.boot" version "4.0.0-M2"
 	id "io.spring.dependency-management" version "1.1.0"
 	id "java"
 }