Ubuntu　Cythonをダウングレードしようとするとエラーになる

現在のCythonのバージョン　0.19.19

実行したコード
~$ pip3 install --upgrade cython==0.29.9
※pipで実行しても同様のエラーになります

エラー

Defaulting to user installation because normal site-packages is not writeable
Collecting cython==0.29.9
  Downloading Cython-0.29.9.tar.gz (2.0 MB)
     |████████████████████████████████| 2.0 MB 2.4 MB/s 
Building wheels for collected packages: cython
  Building wheel for cython (setup.py) ... error
  ERROR: Command errored out with exit status 1:
   command: /usr/local/bin/python3.8 -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-el02slmx/cython/setup.py'"'"'; __file__='"'"'/tmp/pip-install-el02slmx/cython/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' bdist_wheel -d /tmp/pip-wheel-8pur5x4o
       cwd: /tmp/pip-install-el02slmx/cython/
  Complete output (581 lines):
  Unable to find pgen, not compiling formal grammar.
  running bdist_wheel
    :
  creating build/temp.linux-x86_64-3.8/tmp/pip-install-el02slmx/cython/Cython/Plex
  gcc -pthread -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -fPIC -I/usr/local/include/python3.8 -c /tmp/pip-install-el02slmx/cython/Cython/Plex/Scanners.c -o build/temp.linux-x86_64-3.8/tmp/pip-install-el02slmx/cython/Cython/Plex/Scanners.o
  /tmp/pip-install-el02slmx/cython/Cython/Plex/Scanners.c: In function ‘__Pyx_InitCachedConstants’:
  /usr/local/include/python3.8/code.h:72:25: warning: passing argument 6 of ‘PyCode_New’ makes pointer from integer without a cast [-Wint-conversion]
   #define CO_OPTIMIZED    0x0001
                           ^
  /tmp/pip-install-el02slmx/cython/Cython/Plex/Scanners.c:333:37: note: in definition of macro ‘__Pyx_PyCode_New’
             PyCode_New(a, 0, k, l, s, f, code, c, n, v, fv, cell, fn, name, fline, lnos)
                                       ^
     :
  /tmp/pip-install-el02slmx/cython/Cython/Plex/Scanners.c:10030:15: note: in expansion of macro ‘__Pyx_PyCode_New’
       py_code = __Pyx_PyCode_New(
                 ^
  In file included from /usr/local/include/python3.8/compile.h:5:0,
                   from /usr/local/include/python3.8/Python.h:138,
                   from /tmp/pip-install-el02slmx/cython/Cython/Plex/Scanners.c:19:
  /usr/local/include/python3.8/code.h:122:28: note: declared here
   PyAPI_FUNC(PyCodeObject *) PyCode_New(
                              ^
  error: command 'gcc' failed with exit status 1
    ----------------------------------------
  Rolling back uninstall of Cython
　　　:
  Moving to /home/ubun/.local/lib/python3.8/site-packages/pyximport/
   from /home/ubun/.local/lib/python3.8/site-packages/~yximport
ERROR: Command errored out with exit status 1: /usr/local/bin/python3.8 -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-el02slmx/cython/setup.py'"'"'; __file__='"'"'/tmp/pip-install-el02slmx/cython/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /tmp/pip-record-42ndizne/install-record.txt --single-version-externally-managed --user --prefix= --compile --install-headers /home/ubun/.local/include/python3.8/cython Check the logs for full command output.