Update typescript-eslint to 3.4.1-alpha.1 (#39260)

Author: rbuckton

package.json

@@ -54,9 +54,9 @@
         "@types/through2": "latest",
         "@types/travis-fold": "latest",
         "@types/xml2js": "^0.4.0",
-        "@typescript-eslint/eslint-plugin": "^3.4.0",
-        "@typescript-eslint/experimental-utils": "^3.4.0",
-        "@typescript-eslint/parser": "^3.4.0",
+        "@typescript-eslint/eslint-plugin": "^3.4.1-alpha.1",
+        "@typescript-eslint/experimental-utils": "^3.4.1-alpha.1",
+        "@typescript-eslint/parser": "^3.4.1-alpha.1",
         "async": "latest",
         "azure-devops-node-api": "^10.1.0",
         "browser-resolve": "^1.11.2",