dockerfiles: replace format/% notation with f-strings using flynt

These changes were performed by flynt automatically.

No change in behavior intended.

Signed-off-by: Bastian Krause <[email protected]>

Author: Bastian-Krause

Diff for: dockerfiles/staging/client/simple-test/remote_shell_test.py

@@ -5,4 +5,4 @@ def test_shell(target):
     stdout, stderr, returncode = ssh_driver.run('uname -r')
 
     assert stdout
-    print('Kernel {}'.format(stdout))
+    print(f'Kernel {stdout}')