OpenVPN v2.6.4 release

2023.05.11 -- Version 2.6.4

Arne Schwabe (3):
      Remove unused variable line
      Add Apache2 linking with for new commits
      Fix compile error on TARGET_ANDROID

Frank Lichtenheld (2):
      man page: Remove cruft from --topology documentation
      tests: do not include t_client.sh in dist

Kristof Provost (1):
      DCO: support key rotation notifications

Michael Nix (1):
      fix typo in help text: --ignore-unknown-option

Selva Nair (2):
      Format Windows error message in Unicode
      Bugfix: dangling pointer passed to pkcs11-helper