Change to logging.file.name for latest spring-boot

Change-Id: Ibfafb6ebeae242bcc092f8517afd1be5fb991e6a
Issue-ID: NONRTRIC-293
Signed-off-by: RehanRaza <muhammad.rehan.raza@est.tech>
diff --git a/policy-agent/config/application.yaml b/policy-agent/config/application.yaml
index e9146e0..4f5e242 100644
--- a/policy-agent/config/application.yaml
+++ b/policy-agent/config/application.yaml
@@ -18,7 +18,8 @@
     org.springframework.data: ERROR
     org.springframework.web.reactive.function.client.ExchangeFunctions: ERROR
     org.oransc.policyagent: INFO
-  file: /var/log/policy-agent/application.log
+  file:
+    name: /var/log/policy-agent/application.log
 server:
    port : 8433
    http-port: 8081