Fix yarn.lock and update HOWTO_RELEASE

In previous commit I updated all the dependencies with the newest
versions when I really intended to update just one. After asking the
node gurus we agreed on changing the docs to reflect a less aggressive
strategy for dependency upgrades.

HOWTO_RELEASE

@@ -1,7 +1,7 @@
 1. Test (make clean all check), fix if broken before proceeding
 2. Ensure proper version in package.json
 3. Ensure NEWS section exists for the new version, review it, add release date
-4. Recreate yarn.lock with: `yarn upgrade`
+4. If there are modified dependencies in package.json, update them with `yarn upgrade {{package_name}}@{{version}}`
 5. Commit package.json, yarn.lock, NEWS
 6. git tag -a Major.Minor.Patch # use NEWS section as content
 7. Stub NEWS/package for next version

NEWS.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## 3.9.4
+Released 2017-06-22
+
+Announcements:
+ - Upgrades camshaft to [0.55.6](https://github.com/CartoDB/camshaft/releases/tag/0.55.6).
+
 ## 3.9.3
 Released 2017-06-16
 

package.json

@@ -1,7 +1,7 @@
 {
   "private": true,
   "name": "windshaft-cartodb",
-  "version": "3.9.3",
+  "version": "3.9.4",
   "description": "A map tile server for CartoDB",
   "keywords": [
     "cartodb"
@@ -20,7 +20,7 @@
   ],
   "dependencies": {
     "body-parser": "~1.14.0",
-    "camshaft": "0.55.5",
+    "camshaft": "0.55.6",
     "cartodb-psql": "0.8.0",
     "cartodb-query-tables": "0.2.0",
     "cartodb-redis": "0.13.2",

yarn.lock

@@ -198,9 +198,9 @@ camelcase@^3.0.0:
   version "3.0.0"
   resolved "https://registry.yarnpkg.com/camelcase/-/camelcase-3.0.0.tgz#32fc4b9fcdaf845fcdf7e73bb97cac2261f0ab0a"
 
-camshaft@0.55.5:
-  version "0.55.5"
-  resolved "https://registry.yarnpkg.com/camshaft/-/camshaft-0.55.5.tgz#6831f74022b06e12ddab8e00953c7cc859598ac4"
+camshaft@0.55.6:
+  version "0.55.6"
+  resolved "https://registry.yarnpkg.com/camshaft/-/camshaft-0.55.6.tgz#11af28051c3b911fb023ae1cafb165bbd040f174"
   dependencies:
     async "^1.5.2"
     bunyan "1.8.1"