backend-test-utils: migrate to use exports

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

packages/backend-test-utils/package.json

@@ -5,10 +5,17 @@
   "main": "src/index.ts",
   "types": "src/index.ts",
   "publishConfig": {
-    "access": "public",
-    "main": "dist/index.cjs.js",
-    "types": "dist/index.d.ts",
-    "alphaTypes": "dist/index.alpha.d.ts"
+    "access": "public"
+  },
+  "exports": {
+    ".": "./src/index.ts"
+  },
+  "typesVersions": {
+    "*": {
+      "*": [
+        "src/index.ts"
+      ]
+    }
   },
   "backstage": {
     "role": "node-library"
@@ -25,7 +32,7 @@
   ],
   "license": "Apache-2.0",
   "scripts": {
-    "build": "backstage-cli package build --experimental-type-build",
+    "build": "backstage-cli package build",
     "lint": "backstage-cli package lint",
     "test": "backstage-cli package test",
     "prepack": "backstage-cli package prepack",
@@ -55,7 +62,6 @@
     "supertest": "^6.1.3"
   },
   "files": [
-    "dist",
-    "alpha"
+    "dist"
   ]
 }