Upgrade to PyInstaller 4.3

[phw]

Summary

• This is a…
  • Bug fix
  • Feature addition
  • Refactoring
  • Minor / simple change (like a typo)
  • Other
• Describe this change in 1-2 sentences:

Problem

• JIRA ticket (optional): PICARD-XXX

Use latest PyInstaller 4.3, see https://pyinstaller.readthedocs.io/en/stable/CHANGES.html#id1 for details.

For us interesting is the fix for pyinstaller/pyinstaller#5579:

Windows: Set EXE checksums. Reduces false-positive detection from antiviral software.

Having anti virus software detecting Picard or other PyInstaller based software as false positive is a recurring scheme. If this change reduces it that'd be great.