[MSHADE-379] Upgrade ASM to 9.0 (Java 16 support)

diff --git a/pom.xml b/pom.xml
index 16d2de8..30e3814 100644
--- a/pom.xml
+++ b/pom.xml
@@ -68,7 +68,7 @@
     <mavenVersion>3.0</mavenVersion>
     <javaVersion>7</javaVersion>
     <currentVersion>${project.version}</currentVersion>
-    <asmVersion>8.0.1</asmVersion>
+    <asmVersion>9.0</asmVersion>
     <project.build.outputTimestamp>2020-05-23T15:29:40Z</project.build.outputTimestamp>
   </properties>