Update dependency commons-io:commons-io to v2.15.1

Author: renovate[bot]

build.gradle

@@ -48,7 +48,7 @@ dependencies {
     testRuntimeOnly group: 'org.junit.jupiter', name: 'junit-jupiter-engine', version: '5.8.1'
 
     // For turning InputStream to String
-    testImplementation group: 'commons-io', name: 'commons-io', version: '2.11.0'
+    testImplementation group: 'commons-io', name: 'commons-io', version: '2.15.1'
 
     // For reading the demo vapid keypair from a pem file
     testImplementation group: 'org.bouncycastle', name: 'bcpkix-jdk15on', version: '1.70'