Change publish step to publish react-native-macos npm package.

.ado/publish.yml

@@ -139,3 +139,14 @@ jobs:
         inputs:
           PathtoPublish: '$(Build.StagingDirectory)\final'
           ArtifactName: 'ReactNative-Final'
+
+      - task: CmdLine@2
+        displayName: "Prepare package.json for npm publishing as react-native-macos"
+        inputs:
+          script: node .ado/renamePackageToMac.js
+
+      - task: Npm@1
+        displayName: "Publish react-native-macos to npmjs.org"
+        inputs:
+          command: 'publish'
+          publishEndpoint: 'npmjs'

.ado/renamePackageToMac.js

@@ -0,0 +1,3 @@
+// @ts-check
+const {updatePackageName} = require('./versionUtils');
+updatePackageName('react-native-macos');

.ado/versionUtils.js

@@ -37,9 +37,17 @@ function updateVersionsInFiles() {
     return {releaseVersion, branchVersionSuffix};
 }
 
+function updatePackageName(name) {
+    let pkgJson = JSON.parse(fs.readFileSync(pkgJsonPath, "utf8"));
+    pkgJson.name = name;
+    fs.writeFileSync(pkgJsonPath, JSON.stringify(pkgJson, null, 2));
+    console.log(`Updating package.json to name ${name}`);
+}
+
 module.exports = {
     gatherVersionInfo,
     publishBranchName,
     pkgJsonPath,
-    updateVersionsInFiles
+    updateVersionsInFiles,
+    updatePackageName
 }