fix: output umd build for main key

Author: keithamus

package.json

@@ -2,7 +2,7 @@
   "name": "@github/remote-input-element",
   "version": "0.2.0",
   "description": "An input element that sends its value to a server endpoint and renders the response body.",
-  "main": "dist/index.js",
+  "main": "dist/umd/index.js",
   "module": "dist/index.js",
   "types": "dist/index.d.ts",
   "license": "MIT",
@@ -14,7 +14,7 @@
     "clean": "rm -rf dist",
     "lint": "github-lint",
     "prebuild": "npm run clean && npm run lint",
-    "build": "tsc",
+    "build": "tsc --outDir dist/umd --module umd && tsc",
     "pretest": "npm run build",
     "test": "karma start test/karma.config.js",
     "prepublishOnly": "npm run build",

tsconfig.json

@@ -1,7 +1,7 @@
 {
   "compilerOptions": {
     "module": "esnext",
-    "target": "es2018",
+    "target": "es5",
     "strict": true,
     "declaration": true,
     "outDir": "dist",