chore(instrumentation-grpc): add 'grpc' deprecation notice postinstall script (#3833)

Author: pichlermarc

experimental/CHANGELOG.md

@@ -7,6 +7,9 @@ All notable changes to experimental packages in this project will be documented
 ### :boom: Breaking Change
 
 * fix(exporter-logs-otlp-grpc): change OTLPLogsExporter to OTLPLogExporter [#3819](https://github.com/open-telemetry/opentelemetry-js/pull/3819) @fuaiyi
+* chore(instrumentation-grpc): add 'grpc' deprecation notice postinstall script [#3833](https://github.com/open-telemetry/opentelemetry-js/pull/3833) @pichlermarc
+  * Support for telemetry generation for the [`grpc`](https://www.npmjs.com/package/grpc) module will be dropped in the next release as the package has been
+    deprecated for over 1 year, please migrate to [`@grpc/grpc-js`](https://www.npmjs.com/package/@grpc/grpc-js) to continue receiving telemetry.
 
 ### :rocket: (Enhancement)
 

experimental/packages/opentelemetry-instrumentation-grpc/package.json

@@ -18,7 +18,8 @@
     "watch": "tsc --build --watch",
     "precompile": "lerna run version --scope $(npm pkg get name) --include-dependencies",
     "prewatch": "node ../../../scripts/version-update.js",
-    "peer-api-check": "node ../../../scripts/peer-api-check.js"
+    "peer-api-check": "node ../../../scripts/peer-api-check.js",
+    "postinstall": "node -e \"console.log(\\\"\\x1b[95m%s\\x1b[0m\\\", \\\"@opentelemetry/instrumentation-grpc - warning: The package 'grpc' (https://www.npmjs.com/package/grpc) is deprecated. It will no longer be instrumented in the next release of '@opentelemetry/instrumentation-grpc'. Please migrate to '@grpc/grpc-js' (https://www.npmjs.com/package/@grpc/grpc-js) to continue receiving telemetry.\\\");\""
   },
   "keywords": [
     "opentelemetry",