fix(otlp-transformer): add missing prepublishOnly script (#2998)

Co-authored-by: Valentin Marchaud <[email protected]>

Author: dyladan

experimental/CHANGELOG.md

@@ -11,6 +11,7 @@ All notable changes to experimental packages in this project will be documented
 ### :bug: (Bug Fix)
 
 * fix(sdk-metrics-base): only record non-negative histogram values #3002 @pichlermarc
+* fix(otlp-transformer): include missing prepublishOnly script which ensures esm and esnext build files are created and packaged @dyladan
 
 ### :books: (Refine Doc)
 

experimental/packages/otlp-transformer/package.json

@@ -12,6 +12,7 @@
   "main": "build/src/index.js",
   "repository": "open-telemetry/opentelemetry-js",
   "scripts": {
+    "prepublishOnly": "npm run compile",
     "compile": "tsc --build tsconfig.all.json",
     "clean": "tsc --build --clean tsconfig.all.json",
     "lint": "eslint . --ext .ts",