Update Jackson to 2.9.9

Problem
In order to make util cross building with scala 2.13, we need to move to Jackson
2.9.9 for 2.13 support.

Solution
Upgrade it.

Result
As a bonus, Jackson fixes a bug
FasterXML/jackson-core#531 when feeding async json
parser, remove the `slicedOffset` as now parser records the right position.

Differential Revision: https://phabricator.twitter.biz/D345969

CHANGELOG.rst

@@ -22,6 +22,8 @@ Runtime Behavior Changes
   seen as `c.t.f.ChannelClosedException` instead of a `c.t.f.UnknownChannelException`.
   ``PHAB_ID=D336428``
 
+* finagle: Upgrade to Jackson 2.9.9. ``PHAB_ID=D345969``
+
 19.7.0
 ------
 

build.sbt

@@ -34,7 +34,7 @@ val netty4Http = "io.netty" % "netty-codec-http" % netty4Version
 val netty4Http2 = "io.netty" % "netty-codec-http2" % netty4Version
 val netty4StaticSsl = "io.netty" % "netty-tcnative-boringssl-static" % "2.0.25.Final"
 val opencensusVersion = "0.19.1"
-val jacksonVersion = "2.9.8"
+val jacksonVersion = "2.9.9"
 val jacksonLibs = Seq(
   "com.fasterxml.jackson.core" % "jackson-core" % jacksonVersion,
   "com.fasterxml.jackson.core" % "jackson-databind" % jacksonVersion,