Remove yarn postinstall hack (#1098)

package.json

@@ -35,9 +35,7 @@
         "test": "wsrun test $PKG --fast-exit --serial --exclude-missing",
         "generate_doc": "node ./packages/monorepo-scripts/lib/doc_generate_and_upload.js",
         "test:generate_docs:circleci": "for i in ${npm_package_config_packagesWithDocPages}; do yarn generate_doc --package $i --shouldUpload false --isStaging true || break -1; done;",
-        "lint": "wsrun lint $PKG --fast-exit --parallel --exclude-missing",
-        "comment:postinstall": "HACK: For some reason `yarn` is not setting up symlink properly for types. We temporarily make it manually. Remove this ASAP!",
-        "postinstall": "shx cp -R node_modules/@0xproject/types packages/website/node_modules/@0xproject; shx cp -R node_modules/@0xproject/types packages/sra-report/node_modules/@0xproject; rimraf node_modules/@0xproject/types; shx ln -s ../../packages/types node_modules/@0xproject/types"
+        "lint": "wsrun lint $PKG --fast-exit --parallel --exclude-missing"
     },
     "config": {
         "mnemonic": "concert load couple harbor equip island argue ramp clarify fence smart topic",

yarn.lock

@@ -5331,7 +5331,7 @@ ethers@3.0.22:
     uuid "2.0.1"
     xmlhttprequest "1.8.0"
 
-ethers@^4.0.0-beta.14:
+ethers@4.0.0-beta.14:
   version "4.0.0-beta.14"
   resolved "https://registry.yarnpkg.com/ethers/-/ethers-4.0.0-beta.14.tgz#76aa9257b9c93a7604ff4dc11f2a445d07f6459d"
   dependencies:
@@ -6088,7 +6088,7 @@ ganache-core@0xProject/ganache-core#monorepo-dep:
     ethereumjs-tx "0xProject/ethereumjs-tx#fake-tx-include-signature-by-default"
     ethereumjs-util "^5.2.0"
     ethereumjs-vm "2.3.5"
-    ethereumjs-wallet "~0.6.0"
+    ethereumjs-wallet "0.6.0"
     fake-merkle-patricia-tree "~1.0.1"
     heap "~0.2.6"
     js-scrypt "^0.2.0"