3.8.0

Features:

• Options --upgrade and --upgrade-package are no longer mutually exclusive (#831). Thanks @adamchainz

Bug Fixes:

• Fix --generate-hashes with bare VCS URLs (#812). Thanks @jcushman
• Fix issues with UnicodeError when installing pip-tools from source in some systems (#816). Thanks @AbdealiJK
• Respect --pre option in the input file (#822). Thanks @atugushev
• Option --upgrade-package now works even if the output file does not exist (#831). Thanks @adamchainz