Upgrade jackson to 2.9.7

Core Gerrit exports version 2.9.7 since change I27fc60caf.

Also add dependency on snake-yaml, which is a transitive dependency
of jackson-dataformat-yaml.

Change-Id: I8273608107b9f9af01e2badde47fcf83e5d667e8
diff --git a/external_plugin_deps.bzl b/external_plugin_deps.bzl
index 9b6c7f0..7c6aa5c 100644
--- a/external_plugin_deps.bzl
+++ b/external_plugin_deps.bzl
@@ -1,29 +1,35 @@
 load("//tools/bzl:maven_jar.bzl", "maven_jar")
 
-JACKSON_REV = "2.6.6"
+JACKSON_VER = "2.9.7"
 
 def external_plugin_deps(omit_jackson_core = True):
     if not omit_jackson_core:
         maven_jar(
             name = "jackson-core",
-            artifact = "com.fasterxml.jackson.core:jackson-core:%s" % JACKSON_REV,
-            sha1 = "02eb801df67aacaf5b1deb4ac626e1964508e47b",
+            artifact = "com.fasterxml.jackson.core:jackson-core:" + JACKSON_VER,
+            sha1 = "4b7f0e0dc527fab032e9800ed231080fdc3ac015",
         )
 
     maven_jar(
         name = "jackson-databind",
-        artifact = "com.fasterxml.jackson.core:jackson-databind:%s" % JACKSON_REV,
-        sha1 = "5108dde6049374ba980b360e1ecff49847baba4a",
+        artifact = "com.fasterxml.jackson.core:jackson-databind:" + JACKSON_VER,
+        sha1 = "e6faad47abd3179666e89068485a1b88a195ceb7",
     )
 
     maven_jar(
         name = "jackson-annotations",
-        artifact = "com.fasterxml.jackson.core:jackson-annotations:%s" % JACKSON_REV,
-        sha1 = "7ef6440e71531604aa44a5eb62d4b466ffbf7e8f",
+        artifact = "com.fasterxml.jackson.core:jackson-annotations:" + JACKSON_VER,
+        sha1 = "4b838e5c4fc17ac02f3293e9a558bb781a51c46d",
     )
 
     maven_jar(
         name = "jackson-dataformat-yaml",
-        artifact = "com.fasterxml.jackson.dataformat:jackson-dataformat-yaml:%s" % JACKSON_REV,
-        sha1 = "d5c23915aa943541c38065a72ed50941f2fd278d",
+        artifact = "com.fasterxml.jackson.dataformat:jackson-dataformat-yaml:" + JACKSON_VER,
+        sha1 = "a428edc4bb34a2da98a50eb759c26941d4e85960",
+    )
+
+    maven_jar(
+        name = "snakeyaml",
+        artifact = "org.yaml:snakeyaml:1.23",
+        sha1 = "ec62d74fe50689c28c0ff5b35d3aebcaa8b5be68",
     )
diff --git a/owners-common/common.bzl b/owners-common/common.bzl
index c033b84..f766ff2 100644
--- a/owners-common/common.bzl
+++ b/owners-common/common.bzl
@@ -3,4 +3,5 @@
     "@jackson-databind//jar",
     "@jackson-annotations//jar",
     "@jackson-dataformat-yaml//jar",
+    "@snakeyaml//jar",
 ]