match NPM_TOKEN's environment variable name to official documentation

Author: yaacovCR

.changeset/brave-buckets-double.md

@@ -0,0 +1,7 @@
+---
+"@changesets/action": major
+---
+
+use `NODE_AUTH_TOKEN` as the environment variable name for the `NPM_TOKEN` secret
+
+This matches the official GitHub `setup-node` action (documentation)[https://docs.github.com/en/actions/publishing-packages/publishing-nodejs-packages#publishing-packages-to-the-npm-registry].

src/index.ts

@@ -73,14 +73,14 @@ const getOptionalInput = (name: string) => core.getInput(name) || undefined;
           );
           fs.appendFileSync(
             userNpmrcPath,
-            `\n//registry.npmjs.org/:_authToken=\$\{NPM_TOKEN\}\n`
+            `\n//registry.npmjs.org/:_authToken=\$\{NODE_AUTH_TOKEN\}\n`
           );
         }
       } else {
         console.log("No user .npmrc file found, creating one");
         fs.writeFileSync(
           userNpmrcPath,
-          `//registry.npmjs.org/:_authToken=\$\{NPM_TOKEN\}\n`
+          `//registry.npmjs.org/:_authToken=\$\{NODE_AUTH_TOKEN\}\n`
         );
       }