Fix the build break because of incorrect usage of writeFileSync

appveyor.yml

@@ -10,8 +10,10 @@ install:
   - npm --version
   - cd build
   - npm install
+  - npm list
   - cd ../tests
   - npm install
+  - npm list
   - npm test
 
 # Don't actually build.

build/build.ts

@@ -5,7 +5,7 @@ import plist = require('plist');
 
 function writePlistFile(grammar: any, fileName: string) {
     const text = plist.build(grammar);
-    fs.writeFileSync(fileName, text, "utf8");
+    fs.writeFileSync(fileName, text);
 }
 
 function readYaml(fileName: string) {

tests/test.ts

@@ -34,7 +34,7 @@ for (const fileName of fs.readdirSync('cases')) {
 
 function addTestCase(file: string, generatedText: string) {
     const generatedFileName = path.join(generatedFolder, file);
-    fs.writeFileSync(generatedFileName, generatedText, "utf8");
+    fs.writeFileSync(generatedFileName, generatedText);
 
     it('Comparing generated' + file, () => {
         const baselineFile = path.join(baselineFolder, file);