Add back cwd input (#718)

src/pack/index.ts

@@ -17,8 +17,7 @@ try {
 }
 
 async function main() {
-  // If the user needs to change the cwd, set `working-directory` in the step instead
-  const cwd = process.cwd();
+  const cwd = getOptionalInput("cwd") || process.cwd();
   await validateChangesetsCliVersion(cwd);
 
   const publishPlanArtifactId = getOptionalInput("publish-plan-artifact-id");