Drop diff. (#2592)

package.json

@@ -15,7 +15,6 @@
     "debug": "^2.2.0",
     "defaults": "^1.0.3",
     "detect-indent": "^5.0.0",
-    "diff": "^2.2.1",
     "ini": "^1.3.4",
     "inquirer": "^3.0.1",
     "invariant": "^2.2.0",

yarn.lock

@@ -1333,10 +1333,6 @@ detect-newline@2.X:
   version "2.1.0"
   resolved "https://registry.yarnpkg.com/detect-newline/-/detect-newline-2.1.0.tgz#f41f1c10be4b00e87b5f13da680759f2c5bfd3e2"
 
-diff@^2.2.1:
-  version "2.2.3"
-  resolved "https://registry.yarnpkg.com/diff/-/diff-2.2.3.tgz#60eafd0d28ee906e4e8ff0a52c1229521033bf99"
-
 diff@^3.0.0:
   version "3.2.0"
   resolved "https://registry.yarnpkg.com/diff/-/diff-3.2.0.tgz#c9ce393a4b7cbd0b058a725c93df299027868ff9"
@@ -1841,7 +1837,7 @@ form-data@~2.1.1:
 
 fs-exists-sync@^0.1.0:
   version "0.1.0"
-  resolved "https://registry.yarnpkg.com/fs-exists-sync/-/fs-exists-sync-0.1.0.tgz#982d6893af918e72d08dec9e8673ff2b5a8d6add"
+  resolved "http://registry.npmjs.org/fs-exists-sync/-/fs-exists-sync-0.1.0.tgz#982d6893af918e72d08dec9e8673ff2b5a8d6add"
 
 fs.realpath@^1.0.0:
   version "1.0.0"
@@ -2482,7 +2478,7 @@ is-path-inside@^1.0.0:
 
 is-posix-bracket@^0.1.0:
   version "0.1.1"
-  resolved "https://registry.yarnpkg.com/is-posix-bracket/-/is-posix-bracket-0.1.1.tgz#3334dc79774368e92f016e6fbc0a88f5cd6e6bc4"
+  resolved "http://registry.npmjs.org/is-posix-bracket/-/is-posix-bracket-0.1.1.tgz#3334dc79774368e92f016e6fbc0a88f5cd6e6bc4"
 
 is-primitive@^2.0.0:
   version "2.0.0"