Enh: Correct way of pulling relevant branch

Author: klieret

codeclash/agents/player.py

@@ -50,7 +50,8 @@ def __init__(
         self.logger.info(f"Pulling latest changes from origin for {self.name}")
         assert_zero_exit_code(self.environment.execute("git pull origin"), logger=self.logger)
         if branch := config.get("branch_init"):
-            self.logger.info(f"Checkout out branch {branch}")
+            self.logger.info(f"Fetching and checking out branch {branch}")
+            assert_zero_exit_code(self.environment.execute(f"git fetch origin {branch}"), logger=self.logger)
             assert_zero_exit_code(self.environment.execute(f"git checkout {branch}"), logger=self.logger)
 
         if self.push: