Add the ENTERPRISE_REPOSITORY env var to let user consume artifacts from their personal maven mirror

Author: cipolleschi

packages/react-native/sdks/hermes-engine/hermes-utils.rb

@@ -204,7 +204,10 @@ def hermestag_file(react_native_path)
 end
 
 def release_tarball_url(version, build_type)
-    maven_repo_url = "https://repo1.maven.org/maven2"
+    maven_repo_url =
+        ENV['ENTERPRISE_REPOSITORY'] != nil && ENV['ENTERPRISE_REPOSITORY'] != "" ?
+        ENV['ENTERPRISE_REPOSITORY'] :
+        "https://repo1.maven.org/maven2"
     namespace = "com/facebook/react"
     # Sample url from Maven:
     # https://repo1.maven.org/maven2/com/facebook/react/react-native-artifacts/0.71.0/react-native-artifacts-0.71.0-hermes-ios-debug.tar.gz