fix: build issue #3 (#4)

Author: johanneskares

package.json

@@ -3,7 +3,7 @@
   "version": "1.1.1",
   "description": "An Ethers.js compatible signer that connects to GCP KMS",
   "main": "dist/signer.js",
-  "types": "dist/**/*.d.ts",
+  "types": "dist/signer.d.ts",
   "scripts": {
     "type-check": "tsc --noEmit",
     "test": "jest",