Use gnu tar format for the bug reports (#4548)

This change enforces the GNU format of tar files instead of the default
POSIX.1-2001 pax format. This is necessary because:
- the filenames in the bug reports are often longer than the
format-portable restriction of 256 characters
- the Haskell
[library](https://hackage.haskell.org/package/tar-0.6.3.0/changelog) we
use to work with tar does not support the pax format. However, it does
support the GNU format which also allows long names.

pyk/src/pyk/utils.py

@@ -681,7 +681,7 @@ def __init__(self, bug_report: Path) -> None:
     def add_file(self, finput: Path, arcname: Path) -> None:
         if str(finput) not in self._file_remap:
             self._file_remap[str(finput)] = str(arcname)
-            with tarfile.open(self._bug_report, 'a') as tar:
+            with tarfile.open(self._bug_report, 'a', format=tarfile.GNU_FORMAT) as tar:
                 tar.add(finput, arcname=arcname)
                 _LOGGER.info(f'Added file to bug report {self._bug_report}:{arcname}: {finput}')