bugfix: crear changelog cuando no existe

src/git_flow/changelog.py

@@ -16,8 +16,6 @@ class Changelog:
 
         return f"""## {title} - {now.strftime("%F")}
 
-### Commits
-
 """
 
     def generate_content(self, base: str, branch: str):
@@ -56,5 +54,6 @@ class Changelog:
         if isfile(self.FILENAME):
             with open(self.FILENAME, "r") as f:
                 content += f.read()
+
         with open(self.FILENAME, "w") as f:
             f.write(content)