fix: Update Gemma model name in auto_commit.py

Author: ttpho

auto_commit.py

@@ -5,7 +5,7 @@
 model = "gemma3:4b"
 prompt = f"""
 Given the following Git diff and the list of changed files (with file types), suggest a single concise and relevant commit message that best summarizes all the changes made. Use a conventional commit style (e.g., feat:, fix:, chore:, docs:, refactor:). The message should be no longer than 72 characters.
-Just return the commit messages without any additional text or explanation.
+Just return the commit messages without any additional text or explanation, without any Markdown formatting.
 Input:
     Git Diff:
         [Git Diff]