Update ktor monorepo to v2.3.13

Author: renovate[bot]

backend/build.gradle.kts

@@ -16,11 +16,11 @@ kotlin {
             implementation(libs.kotlinx.coroutines)
             implementation(libs.kotlinx.serialization)
 
-            implementation("io.ktor:ktor-server-core:2.3.12")
-            implementation("io.ktor:ktor-server-netty:2.3.12")
-            implementation("io.ktor:ktor-server-cors:2.3.12")
-            implementation("io.ktor:ktor-serialization-kotlinx-json:2.3.12")
-            implementation("io.ktor:ktor-server-content-negotiation:2.3.12")
+            implementation("io.ktor:ktor-server-core:2.3.13")
+            implementation("io.ktor:ktor-server-netty:2.3.13")
+            implementation("io.ktor:ktor-server-cors:2.3.13")
+            implementation("io.ktor:ktor-serialization-kotlinx-json:2.3.13")
+            implementation("io.ktor:ktor-server-content-negotiation:2.3.13")
 
             implementation("ch.qos.logback:logback-classic:1.5.8")