Add springFrameworkVersion property in gradle

Closes gh-9954

dependencies/spring-security-dependencies.gradle

@@ -7,7 +7,7 @@ javaPlatform {
 }
 
 dependencies {
-	api platform("org.springframework:spring-framework-bom:5.3.7")
+	api platform("org.springframework:spring-framework-bom:$springFrameworkVersion")
 	api platform("io.projectreactor:reactor-bom:2020.0.7")
 	api platform("io.rsocket:rsocket-bom:1.1.0")
 	api platform("org.springframework.data:spring-data-bom:2021.0.1")

gradle.properties

@@ -1,6 +1,7 @@
 aspectjVersion=1.9.6
 springJavaformatVersion=0.0.28
 springBootVersion=2.4.2
+springFrameworkVersion=5.3.7
 openSamlVersion=3.4.6
 version=5.6.0-SNAPSHOT
 kotlinVersion=1.5.0