Update iOS library + Potential CI fixes (#609)

* Update iOS SDK to latest version. Regenerate yarn.lock for main repo to fix CI issues with yarn and add lock file for example project

* Update yarn on travis

* Remove example yarn.lock due to integrity check issues

* Also ignore package lock in example folder

.gitignore

@@ -52,6 +52,7 @@ node_modules
 .nvm
 /bots/node_modules/
 package-lock.json
+/example/package-lock.json
 
 # OS X
 .DS_Store

.travis.yml

@@ -5,7 +5,7 @@ matrix:
       before_install:
         - nvm install 8
         - echo yes | sdkmanager "platforms;android-28"
-        - curl -o- -L https://yarnpkg.com/install.sh | bash -s -- --version 1.16.0
+        - curl -o- -L https://yarnpkg.com/install.sh | bash -s -- --version 1.21.1
         - export PATH=$HOME/.yarn/bin:$PATH
       android:
         components:
@@ -40,7 +40,7 @@ matrix:
       podfile: example/ios/Podfile
 
 before_install:
-  - curl -o- -L https://yarnpkg.com/install.sh | bash -s -- --version 1.16.0
+  - curl -o- -L https://yarnpkg.com/install.sh | bash -s -- --version 1.21.1
   - export PATH=$HOME/.yarn/bin:$PATH
 
 install:
@@ -83,4 +83,4 @@ deploy:
   on:
     tags: true
     repo: react-native-mapbox-gl/maps
-    branch: master
+    branch: master

package.json

@@ -20,7 +20,7 @@
     "url": "https://github.com/react-native-mapbox-gl/maps"
   },
   "scripts": {
-    "fetch:ios:sdk": "node ./scripts/download-mapbox-gl-native-ios-if-on-mac.js 5.5.0",
+    "fetch:ios:sdk": "node ./scripts/download-mapbox-gl-native-ios-if-on-mac.js 5.6.1",
     "fetch:style:spec": ". ./scripts/download-style-spec.sh",
     "generate": "node ./scripts/autogenerate",
     "preinstall": "npm run fetch:ios:sdk",