build: update terser to version 4.6.3

(cherry picked from commit cca12e1)

Author: clydin

packages/angular_devkit/build_angular/package.json

@@ -54,7 +54,7 @@
     "stylus": "0.54.5",
     "stylus-loader": "3.0.2",
     "tree-kill": "1.2.2",
-    "terser": "4.3.9",
+    "terser": "4.6.3",
     "terser-webpack-plugin": "1.4.3",
     "webpack": "4.39.2",
     "webpack-dev-middleware": "3.7.2",

yarn.lock

@@ -10270,7 +10270,16 @@ terser-webpack-plugin@^1.4.1:
     webpack-sources "^1.4.0"
     worker-farm "^1.7.0"
 
-[email protected], terser@^4.1.2:
+[email protected]:
+  version "4.6.3"
+  resolved "https://registry.yarnpkg.com/terser/-/terser-4.6.3.tgz#e33aa42461ced5238d352d2df2a67f21921f8d87"
+  integrity sha512-Lw+ieAXmY69d09IIc/yqeBqXpEQIpDGZqT34ui1QWXIUpR2RjbqEkT8X7Lgex19hslSqcWM5iMN2kM11eMsESQ==
+  dependencies:
+    commander "^2.20.0"
+    source-map "~0.6.1"
+    source-map-support "~0.5.12"
+
+terser@^4.1.2:
   version "4.3.9"
   resolved "https://registry.yarnpkg.com/terser/-/terser-4.3.9.tgz#e4be37f80553d02645668727777687dad26bbca8"
   integrity sha512-NFGMpHjlzmyOtPL+fDw3G7+6Ueh/sz4mkaUYa4lJCxOPTNzd0Uj0aZJOmsDYoSQyfuVoWDMSWTPU3huyOm2zdA==