Add workaround to fix BOM-related error during parsing global.json

Author: Sergey Dolin

src/setup-dotnet.ts

@@ -20,7 +20,8 @@ export async function run() {
       const globalJsonPath = path.join(process.cwd(), 'global.json');
       if (fs.existsSync(globalJsonPath)) {
         const globalJson = JSON.parse(
-          fs.readFileSync(globalJsonPath, {encoding: 'utf8'})
+          // .trim() is necessary to strip BOM https://github.com/nodejs/node/issues/20649
+          fs.readFileSync(globalJsonPath, {encoding: 'utf8'}).trim()
         );
         if (globalJson.sdk && globalJson.sdk.version) {
           version = globalJson.sdk.version;