Updating to imageio-ext 1.4.15

Author: aaime

geowebcache/pom.xml

@@ -76,7 +76,7 @@
     <jalopy.srcExcludesPattern>disabled</jalopy.srcExcludesPattern>
     <test.maxHeapSize>64M</test.maxHeapSize>
     <maven.test.jvmargs></maven.test.jvmargs>
-    <imageio-ext.version>1.4.14</imageio-ext.version>
+    <imageio-ext.version>1.4.15</imageio-ext.version>
     <hazelcast.version>5.3.8</hazelcast.version>
     <joda-time.version>2.8.1</joda-time.version>
     <spotless.action>apply</spotless.action>