Upgrade buildSrc to Spring Framework 5.3.15

Closes gh-29545

buildSrc/build.gradle

@@ -15,6 +15,7 @@ targetCompatibility = 1.8
 
 dependencies {
 	checkstyle "io.spring.javaformat:spring-javaformat-checkstyle:${javaFormatVersion}"
+	implementation(platform("org.springframework:spring-framework-bom:5.3.15"))
 	implementation("com.fasterxml.jackson.core:jackson-databind:2.11.4")
 	implementation("commons-codec:commons-codec:1.13")
 	implementation("org.apache.maven:maven-embedder:3.6.2")
@@ -22,8 +23,8 @@ dependencies {
 	implementation("org.gradle:test-retry-gradle-plugin:1.3.1")
 	implementation("org.jetbrains.kotlin:kotlin-gradle-plugin:1.5.0")
 	implementation("org.jetbrains.kotlin:kotlin-compiler-embeddable:1.5.0")
-	implementation("org.springframework:spring-core:5.2.2.RELEASE")
-	implementation("org.springframework:spring-web:5.2.2.RELEASE")
+	implementation("org.springframework:spring-core")
+	implementation("org.springframework:spring-web")
 	implementation("io.spring.javaformat:spring-javaformat-gradle-plugin:${javaFormatVersion}")
 	testImplementation("org.assertj:assertj-core:3.11.1")
 	testImplementation("org.apache.logging.log4j:log4j-core:2.17.1")