Added sourcemap-codec dev dependency

Author: Brian Vaughn

packages/react-devtools-extensions/package.json

@@ -50,6 +50,7 @@
     "rollup-plugin-commonjs": "^9.3.4",
     "rollup-plugin-node-resolve": "^2.1.1",
     "source-map": "^0.8.0-beta.0",
+    "sourcemap-codec": "^1.4.8",
     "style-loader": "^0.23.1",
     "web-ext": "^3.0.0",
     "webpack": "^4.43.0",

yarn.lock

@@ -13047,7 +13047,7 @@ source-map@^0.8.0-beta.0:
   dependencies:
     whatwg-url "^7.0.0"
 
-sourcemap-codec@^1.4.1, sourcemap-codec@^1.4.4:
+sourcemap-codec@^1.4.1, sourcemap-codec@^1.4.4, sourcemap-codec@^1.4.8:
   version "1.4.8"
   resolved "https://registry.yarnpkg.com/sourcemap-codec/-/sourcemap-codec-1.4.8.tgz#ea804bd94857402e6992d05a38ef1ae35a9ab4c4"
   integrity sha512-9NykojV5Uih4lgo5So5dtw+f0JgJX30KCNI8gwhz2J9A15wD0Ml6tjHKwf6fTSa6fAdVBdZeNOs9eJ71qCk8vA==