Add newline to changelog after section header

Author: internettrans

.changelog/01.txt

@@ -0,0 +1,2 @@
+fix
+Add newline in changelog between header and first item

src/changelog-utils.js

@@ -55,7 +55,7 @@ export async function prepareRelease() {
   existingFiles.sort();
 
   let versionBump = "";
-  const newChangelogLines = [""];
+  const newChangelogLines = ["\n"];
 
   for (let existingFile of existingFiles) {
     const filePath = path.resolve(process.cwd(), ".changelog", existingFile);