Update log4j2 version to 2.17.0

Updated version fix DoS vulnerability found for 2.15 (CVE-2021-45046)

Change-Id: Ifeb9170fcbc73150a842ef0c3f3e683cc5c65009

external_plugin_deps.bzl

diff --git a/external_plugin_deps.bzl b/external_plugin_deps.bzl
index eabfac9..4c582f0 100644
--- a/external_plugin_deps.bzl
+++ b/external_plugin_deps.bzl
@@ -52,24 +52,24 @@
         sha1 = "31cdf122e000322e9efcb38913e9ab07825b17ef",
     )
 
-    LOG4J2_VERS = "2.16.0"
+    LOG4J2_VERS = "2.17.0"
 
     maven_jar(
         name = "log4j-slf4j-impl",
         artifact = "org.apache.logging.log4j:log4j-slf4j-impl:" + LOG4J2_VERS,
-        sha1 = "d4cc7712ebb4744681db815679248e4312f61b32",
+        sha1 = "1ec25ce0254749c94549ea9c3cea34bd0488c9c6",
     )
 
     maven_jar(
         name = "log4j-core",
         artifact = "org.apache.logging.log4j:log4j-core:" + LOG4J2_VERS,
-        sha1 = "ca12fb3902ecfcba1e1357ebfc55407acec30ede",
+        sha1 = "fe6e7a32c1228884b9691a744f953a55d0dd8ead",
     )
 
     maven_jar(
         name = "log4j-api",
         artifact = "org.apache.logging.log4j:log4j-api:" + LOG4J2_VERS,
-        sha1 = "4727d93a76616ffc4149dffac5801827c0f4ac71",
+        sha1 = "bbd791e9c8c9421e45337c4fe0a10851c086e36c",
     )
 
     maven_jar(