fix linter

tools/modify_readme.py

@@ -7,9 +7,9 @@ branch_name = sys.argv[2]
 pattern = re.compile("<img\\s+([^>]*?)(?<![\'\"])(?<!\\/)src\\s*=\\s*([\'\"])(?!http|\\/)(.*?)\\2([^>]*?)>")
 replacement = r'<img \1src="https://raw.githubusercontent.com/Avaiga/{repo_name}/{branch_name}/\3"\4>'
 
-with open(f'README.md') as readme_file:
+with open('README.md') as readme_file:
     readme_str = readme_file.read()
     modified_readme = re.sub(pattern, replacement.format(repo_name=repo_name, branch_name=branch_name), readme_str)
 
-with open(f'README.md', 'w') as readme_file:
+with open('README.md', 'w') as readme_file:
     readme_file.write(modified_readme)