Update branch version to 6.6 in package.json (#27760)

* Update branch version to 6.6 in package.json 

This points all the doc links in Kibana to 6.6 branch instead of 6.x

* Updated elasticsearch-browser to 15.3.0

package.json

@@ -12,7 +12,7 @@
   ],
   "private": true,
   "version": "6.6.0",
-  "branch": "6.x",
+  "branch": "6.6",
   "types": "./kibana.d.ts",
   "build": {
     "number": 8467,
@@ -151,8 +151,8 @@
     "d3-cloud": "1.2.1",
     "del": "^3.0.0",
     "dragula": "3.7.0",
-    "elasticsearch": "^15.2.0",
-    "elasticsearch-browser": "^15.2.0",
+    "elasticsearch": "^15.3.0",
+    "elasticsearch-browser": "^15.3.0",
     "encode-uri-query": "1.0.0",
     "execa": "^1.0.0",
     "expiry-js": "0.1.7",

yarn.lock

@@ -7281,10 +7281,10 @@ ejs@^2.2.4, ejs@^2.3.1:
   resolved "https://registry.yarnpkg.com/ejs/-/ejs-2.5.7.tgz#cc872c168880ae3c7189762fd5ffc00896c9518a"
   integrity sha1-zIcsFoiArjxxiXYv1f/ACJbJUYo=
 
-elasticsearch-browser@^15.2.0:
-  version "15.2.0"
-  resolved "https://registry.yarnpkg.com/elasticsearch-browser/-/elasticsearch-browser-15.2.0.tgz#3af0d4b6ffbd125842c7082bbdd99ae4afcba27b"
-  integrity sha512-Rhz7SkuPeiBtRZP2xn98NhiECJQSTrzUEDHXkepkYXqH755kjPzpJB2rvioKDkA+4gegOyHk2yx+VDGcMXQhVg==
+elasticsearch-browser@^15.3.0:
+  version "15.3.0"
+  resolved "https://registry.yarnpkg.com/elasticsearch-browser/-/elasticsearch-browser-15.3.0.tgz#e7214d3f2237e2fd0e22a6203f84f9a523701c7a"
+  integrity sha512-XadGC2BYs1xh/yCrdnuER4ryHuN6xM3C4FS2IVgfazJViUMDEe3J9BSnG5yIMkRURNWX0/ETmW3fheI5zqEpsg==
 
 elasticsearch@^15.2.0:
   version "15.2.0"
@@ -7295,6 +7295,15 @@ elasticsearch@^15.2.0:
     chalk "^1.0.0"
     lodash "^4.17.10"
 
+elasticsearch@^15.3.0:
+  version "15.3.0"
+  resolved "https://registry.yarnpkg.com/elasticsearch/-/elasticsearch-15.3.0.tgz#7a478d23e8af02b60fd03201f1c65fd5657bf7d3"
+  integrity sha512-anZpNB65mqr0aKAN/YPR5OFmD09KnbxBxzyc5vINkip6ECpyCSvBqCKbQNNY/FNwKop2urkRmtnU2sY5cVw1cw==
+  dependencies:
+    agentkeepalive "^3.4.1"
+    chalk "^1.0.0"
+    lodash "^4.17.10"
+
 electron-to-chromium@^1.3.47:
   version "1.3.82"
   resolved "https://registry.yarnpkg.com/electron-to-chromium/-/electron-to-chromium-1.3.82.tgz#7d13ae4437d2a783de3f4efba96b186c540b67b1"