Release bdebstrap 0.2.0

This release changes the default output verbosity to align with mmdebstrap. To restore the previous default behavior, call bdebstrap with --verbose.

• Fix KeyError: 'target' if no target was specified
• Fix passing --target=- (Debian bug #989452)
• Add --silent as alias for --quiet
• Align log levels with mmdebstrap (Debian bug #989450):
  • Change the default log level from info to warning
  • Add a --verbose option to change the log level to info again
  • Pass down --quiet and --debug to mmdebstrap
• Fix PermissionError exception when clamping mtime