upgrade netty to incorporate new aarch_64 classifier

Problem
This is a refresh of #884: "There are new netty releases and the
classifier for AArch64 was changed from linux-aarch64 to
linux-aarch_64. This results in dependency problems with other
projects."

Solution
Upgrade to netty 4.1.59.Final and netty-tcnative 2.0.35.Final
for security fixes and AArch64 dependency rename.

#884 was blocked because of a bug in netty 4.1.56.Final, but
AFAICT this has been fixed in 4.1.59.Final.

Signed-off-by: Jing Yan <jyan@twitter.com>

Differential Revision: https://phabricator.twitter.biz/D629268

CHANGELOG.rst

@@ -19,6 +19,8 @@ New Features
   Also introduced `Backoff.fromStream(Stream)` and `Backoff.toStream` to help with migration to
   the new API. ``PHAB_ID=D592562``
 
+* finagle-netty4: Upgrade to Netty 4.1.59.Final and TcNative 2.0.35.Final. ``PHAB_ID=D629268``  
+
 Breaking API Changes
 ~~~~~~~~~~~~~~~~~~~~
 * finagle: Builds are now only supported for Scala 2.12+ ``PHAB_ID=D631091``

build.sbt

@@ -6,8 +6,8 @@ val releaseVersion = "21.3.0-SNAPSHOT"
 
 val libthriftVersion = "0.10.0"
 
-val defaultNetty4Version = "4.1.51.Final"
-val defaultNetty4StaticSslVersion = "2.0.34.Final"
+val defaultNetty4Version = "4.1.59.Final"
+val defaultNetty4StaticSslVersion = "2.0.35.Final"
 
 val useNettySnapshot: Boolean = sys.env.get("FINAGLE_USE_NETTY_4_SNAPSHOT") match {
   case Some(useSnapshot) => useSnapshot.toBoolean
@@ -44,7 +44,7 @@ val netty4Libs = Seq(
   "io.netty" % "netty-handler" % netty4Version,
   "io.netty" % "netty-transport" % netty4Version,
   "io.netty" % "netty-transport-native-epoll" % netty4Version classifier "linux-x86_64",
-  "io.netty" % "netty-transport-native-epoll" % netty4Version classifier "linux-aarch64",
+  "io.netty" % "netty-transport-native-epoll" % netty4Version classifier "linux-aarch_64",
   // this package is a dep of native-epoll above, explicitly add this for coursier plugin
   "io.netty" % "netty-transport-native-unix-common" % netty4Version,
   "io.netty" % "netty-handler-proxy" % netty4Version
@@ -53,7 +53,7 @@ val netty4LibsTest = Seq(
   "io.netty" % "netty-handler" % netty4Version % "test",
   "io.netty" % "netty-transport" % netty4Version % "test",
   "io.netty" % "netty-transport-native-epoll" % netty4Version % "test" classifier "linux-x86_64",
-  "io.netty" % "netty-transport-native-epoll" % netty4Version classifier "linux-aarch64",
+  "io.netty" % "netty-transport-native-epoll" % netty4Version % "test" classifier "linux-aarch_64",
   // this package is a dep of native-epoll above, explicitly add this for coursier plugin
   "io.netty" % "netty-transport-native-unix-common" % netty4Version % "test",
   "io.netty" % "netty-handler-proxy" % netty4Version % "test",