Exclude okio from vulnerability locations (#7937)

Author: smola

dd-java-agent/instrumentation/iast-instrumenter/src/main/resources/datadog/trace/instrumentation/iastinstrumenter/iast_exclusion.trie

@@ -187,6 +187,7 @@
 1 okhttp3.*
 2 okhttp3.Request
 2 okhttp3.Request$*
+2 okio.*
 1 ognl.*
 2 oracle.j2ee.*
 1 oracle.jdbc.*