Raise stderr dump limit to 50 lines in DGoss error

The default dump_stderr cap of 10 lines is now user-visible since
BakeryDGossError.__str__ prints it. Docker errors are rarely long, but
auth chain failures and daemon traces can exceed 10 lines and would be
silently truncated.

Author: bschwedler

posit-bakery/posit_bakery/plugins/builtin/dgoss/errors.py

@@ -33,7 +33,7 @@ def __str__(self) -> str:
         stdout_dump = self.dump_stdout()
         if stdout_dump:
             s += f"  - Command output:\n{textwrap.indent(stdout_dump, '      ')}\n"
-        stderr_dump = self.dump_stderr()
+        stderr_dump = self.dump_stderr(lines=50)
         if stderr_dump:
             s += f"  - Error output:\n{textwrap.indent(stderr_dump, '      ')}\n"
         s += f"  - Command executed: {' '.join(self.cmd)}\n"