Update dependency org.springframework.security:spring-security-oauth2-client to v5.8.12

Author: renovate[bot]

build.gradle

@@ -88,7 +88,7 @@ dependencies {
     implementation 'org.springframework.boot:spring-boot-starter-actuator'
     implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
     implementation 'org.springframework.boot:spring-boot-starter-security'
-    implementation "org.springframework.security:spring-security-oauth2-client:5.5.8"
+    implementation "org.springframework.security:spring-security-oauth2-client:5.8.12"
     implementation "org.springframework.security.oauth:spring-security-oauth2:2.5.2.RELEASE"
 
     testImplementation 'org.springframework.boot:spring-boot-starter-test'