remove vendored clipboard library in favor of package.json entry

package.json

@@ -26,7 +26,7 @@
     "bootstrap-sass": "^3.3.6",
     "brace-expansion": "^1.1.8",
     "classlist-polyfill": "^1.2.0",
-    "clipboard": "^1.6.1",
+    "clipboard": "^1.7.1",
     "compression-webpack-plugin": "^1.0.0",
     "copy-webpack-plugin": "^4.0.1",
     "core-js": "^2.4.1",

yarn.lock

@@ -1288,13 +1288,13 @@ cli-width@^2.0.0:
   version "2.1.0"
   resolved "https://registry.yarnpkg.com/cli-width/-/cli-width-2.1.0.tgz#b234ca209b29ef66fc518d9b98d5847b00edf00a"
 
-clipboard@^1.5.5, clipboard@^1.6.1:
-  version "1.6.1"
-  resolved "https://registry.yarnpkg.com/clipboard/-/clipboard-1.6.1.tgz#65c5b654812466b0faab82dc6ba0f1d2f8e4be53"
+clipboard@^1.5.5, clipboard@^1.7.1:
+  version "1.7.1"
+  resolved "https://registry.yarnpkg.com/clipboard/-/clipboard-1.7.1.tgz#360d6d6946e99a7a1fef395e42ba92b5e9b5a16b"
   dependencies:
-    good-listener "^1.2.0"
+    good-listener "^1.2.2"
     select "^1.1.2"
-    tiny-emitter "^1.0.0"
+    tiny-emitter "^2.0.0"
 
 cliui@^2.1.0:
   version "2.1.0"
@@ -2883,7 +2883,7 @@ globby@^6.1.0:
     pify "^2.0.0"
     pinkie-promise "^2.0.0"
 
-good-listener@^1.2.0:
+good-listener@^1.2.2:
   version "1.2.2"
   resolved "https://registry.yarnpkg.com/good-listener/-/good-listener-1.2.2.tgz#d53b30cdf9313dffb7dc9a0d477096aa6d145c50"
   dependencies:
@@ -6115,9 +6115,9 @@ timers-browserify@^2.0.2:
   dependencies:
     setimmediate "^1.0.4"
 
-tiny-emitter@^1.0.0:
-  version "1.1.0"
-  resolved "https://registry.yarnpkg.com/tiny-emitter/-/tiny-emitter-1.1.0.tgz#ab405a21ffed814a76c19739648093d70654fecb"
+tiny-emitter@^2.0.0:
+  version "2.0.2"
+  resolved "https://registry.yarnpkg.com/tiny-emitter/-/tiny-emitter-2.0.2.tgz#82d27468aca5ade8e5fd1e6d22b57dd43ebdfb7c"
 
 tmp@0.0.31, tmp@0.0.x:
   version "0.0.31"