Add resolution for lodash.merge security issue

Ref: lodash/lodash#4336
Ref: https://snyk.io/blog/snyk-research-team-discovers-severe-prototype-pollution-security-vulnerabilities-affecting-all-versions-of-lodash/
Ref: mailgun/mailgun.js#48

package.json

@@ -11,5 +11,8 @@
   "private": true,
   "dependencies": {
     "mailgun.js": "^2.0.1"
+  },
+  "resolutions": {
+    "lodash.merge": "^4.6.2"
   }
 }

yarn.lock

@@ -78,16 +78,6 @@ isarray@~1.0.0:
   resolved "https://registry.yarnpkg.com/isarray/-/isarray-1.0.0.tgz#bb935d48582cba168c06834957a54a3e07124f11"
   integrity sha1-u5NdSFgsuhaMBoNJV6VKPgcSTxE=
 
-lodash._arraycopy@^3.0.0:
-  version "3.0.0"
-  resolved "https://registry.yarnpkg.com/lodash._arraycopy/-/lodash._arraycopy-3.0.0.tgz#76e7b7c1f1fb92547374878a562ed06a3e50f6e1"
-  integrity sha1-due3wfH7klRzdIeKVi7Qaj5Q9uE=
-
-lodash._arrayeach@^3.0.0:
-  version "3.0.0"
-  resolved "https://registry.yarnpkg.com/lodash._arrayeach/-/lodash._arrayeach-3.0.0.tgz#bab156b2a90d3f1bbd5c653403349e5e5933ef9e"
-  integrity sha1-urFWsqkNPxu9XGU0AzSeXlkz754=
-
 lodash._arraymap@^3.0.0:
   version "3.0.0"
   resolved "https://registry.yarnpkg.com/lodash._arraymap/-/lodash._arraymap-3.0.0.tgz#1a8fd0f4c0df4b61dea076d717cdc97f0a3c3e66"
@@ -123,11 +113,6 @@ lodash._baseeach@^3.0.0:
   dependencies:
     lodash.keys "^3.0.0"
 
-lodash._basefor@^3.0.0:
-  version "3.0.3"
-  resolved "https://registry.yarnpkg.com/lodash._basefor/-/lodash._basefor-3.0.3.tgz#7550b4e9218ef09fad24343b612021c79b4c20c2"
-  integrity sha1-dVC06SGO8J+tJDQ7YSAhx5tMIMI=
-
 lodash._baseisequal@^3.0.0:
   version "3.0.7"
   resolved "https://registry.yarnpkg.com/lodash._baseisequal/-/lodash._baseisequal-3.0.7.tgz#d8025f76339d29342767dcc887ce5cb95a5b51f1"
@@ -222,15 +207,6 @@ lodash.isarray@^3.0.0:
   resolved "https://registry.yarnpkg.com/lodash.isarray/-/lodash.isarray-3.0.4.tgz#79e4eb88c36a8122af86f844aa9bcd851b5fbb55"
   integrity sha1-eeTriMNqgSKvhvhEqpvNhRtfu1U=
 
-lodash.isplainobject@^3.0.0:
-  version "3.2.0"
-  resolved "https://registry.yarnpkg.com/lodash.isplainobject/-/lodash.isplainobject-3.2.0.tgz#9a8238ae16b200432960cd7346512d0123fbf4c5"
-  integrity sha1-moI4rhayAEMpYM1zRlEtASP79MU=
-  dependencies:
-    lodash._basefor "^3.0.0"
-    lodash.isarguments "^3.0.0"
-    lodash.keysin "^3.0.0"
-
 lodash.istypedarray@^3.0.0:
   version "3.0.6"
   resolved "https://registry.yarnpkg.com/lodash.istypedarray/-/lodash.istypedarray-3.0.6.tgz#c9a477498607501d8e8494d283b87c39281cef62"
@@ -245,14 +221,6 @@ lodash.keys@^3.0.0:
     lodash.isarguments "^3.0.0"
     lodash.isarray "^3.0.0"
 
-lodash.keysin@^3.0.0:
-  version "3.0.8"
-  resolved "https://registry.yarnpkg.com/lodash.keysin/-/lodash.keysin-3.0.8.tgz#22c4493ebbedb1427962a54b445b2c8a767fb47f"
-  integrity sha1-IsRJPrvtsUJ5YqVLRFssinZ/tH8=
-  dependencies:
-    lodash.isarguments "^3.0.0"
-    lodash.isarray "^3.0.0"
-
 lodash.last@^3.0.0:
   version "3.0.0"
   resolved "https://registry.yarnpkg.com/lodash.last/-/lodash.last-3.0.0.tgz#242f663112dd4c6e63728c60a3c909d1bdadbd4c"
@@ -269,22 +237,10 @@ lodash.map@^3.1.4:
     lodash.isarray "^3.0.0"
     lodash.keys "^3.0.0"
 
-lodash.merge@^3.3.2:
-  version "3.3.2"
-  resolved "https://registry.yarnpkg.com/lodash.merge/-/lodash.merge-3.3.2.tgz#0d90d93ed637b1878437bb3e21601260d7afe994"
-  integrity sha1-DZDZPtY3sYeEN7s+IWASYNev6ZQ=
-  dependencies:
-    lodash._arraycopy "^3.0.0"
-    lodash._arrayeach "^3.0.0"
-    lodash._createassigner "^3.0.0"
-    lodash._getnative "^3.0.0"
-    lodash.isarguments "^3.0.0"
-    lodash.isarray "^3.0.0"
-    lodash.isplainobject "^3.0.0"
-    lodash.istypedarray "^3.0.0"
-    lodash.keys "^3.0.0"
-    lodash.keysin "^3.0.0"
-    lodash.toplainobject "^3.0.0"
+lodash.merge@^3.3.2, lodash.merge@^4.6.2:
+  version "4.6.2"
+  resolved "https://registry.yarnpkg.com/lodash.merge/-/lodash.merge-4.6.2.tgz#558aa53b43b661e1925a0afdfa36a9a1085fe57a"
+  integrity sha512-0KpjqXRVvrYyCsX1swR/XTK0va6VQkQM6MNo7PqW77ByjAhoARA8EfrP1N4+KlKj8YS0ZUCtRT/YUuhyYDujIQ==
 
 lodash.pairs@^3.0.0:
   version "3.0.1"
@@ -307,14 +263,6 @@ lodash.restparam@^3.0.0:
   resolved "https://registry.yarnpkg.com/lodash.restparam/-/lodash.restparam-3.6.1.tgz#936a4e309ef330a7645ed4145986c85ae5b20805"
   integrity sha1-k2pOMJ7zMKdkXtQUWYbIWuWyCAU=
 
-lodash.toplainobject@^3.0.0:
-  version "3.0.0"
-  resolved "https://registry.yarnpkg.com/lodash.toplainobject/-/lodash.toplainobject-3.0.0.tgz#28790ad942d293d78aa663a07ecf7f52ca04198d"
-  integrity sha1-KHkK2ULSk9eKpmOgfs9/UsoEGY0=
-  dependencies:
-    lodash._basecopy "^3.0.0"
-    lodash.keysin "^3.0.0"
-
 mailgun.js@^2.0.1:
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/mailgun.js/-/mailgun.js-2.0.1.tgz#13d703e0c25e85da29818a03f1d424a5991d7402"