Update `pyinstaller` dependency for next update.

[Ashvin-Ranjan]

This is because there are some problems with fresh installing it onto a computer sometimes, and this may have been fixed with the new version as we are using a nearly 1 year old version. Here is an example of the problems caused:

Python path configuration:
  PYTHONHOME = 'C:\Users\ranjash24\.n\bin'
  PYTHONPATH = (not set)
  program name = 'C:\Users\ranjash24\.n\bin\n.exe'
  isolated = 0
  environment = 0
  user site = 0
  import site = 0
  sys._base_executable = 'C:\\Users\\ranjash24\\.n\\bin\\n.exe'
  sys.base_prefix = ''
  sys.base_exec_prefix = ''
  sys.platlibdir = 'lib'
  sys.executable = 'C:\\Users\\ranjash24\\.n\\bin\\n.exe'
  sys.prefix = ''
  sys.exec_prefix = ''
  sys.path = [
    'C:\\Users\\ranjash24\\.n\\bin\\base_library.zip',
    'C:\\Users\\ranjash24\\.n\\bin\\lib-dynload',
    'C:\\Users\\ranjash24\\.n\\bin',
  ]
Fatal Python error: init_fs_encoding: failed to get the Python codec of the filesystem encoding
Python runtime state: core initialized
ModuleNotFoundError: No module named 'encodings'

Current thread 0x00000ac4 (most recent call first):
<no Python frame>

This may also be because the computer has no PYTHONPATH set, In which case I will find a fix for that.

Conclusion

Updating is a good idea as new major versions have dropped which might help with speed and bug fixes.