vips: 8.6.3 -> 8.6.4

Semi-automatic update generated by https://github.com/ryantm/nixpkgs-update tools.

This update was made based on information from https://repology.org/metapackage/vips/versions.

These checks were done:

- built on NixOS
- /nix/store/cffal7h8l17axil62hrsmx2lhja9fpmm-vips-8.6.4/bin/vips passed the binary check.
- /nix/store/cffal7h8l17axil62hrsmx2lhja9fpmm-vips-8.6.4/bin/vipsedit passed the binary check.
- /nix/store/cffal7h8l17axil62hrsmx2lhja9fpmm-vips-8.6.4/bin/vipsthumbnail passed the binary check.
- /nix/store/cffal7h8l17axil62hrsmx2lhja9fpmm-vips-8.6.4/bin/vipsheader passed the binary check.
- Warning: no invocation of /nix/store/cffal7h8l17axil62hrsmx2lhja9fpmm-vips-8.6.4/bin/light_correct had a zero exit code or showed the expected version
- Warning: no invocation of /nix/store/cffal7h8l17axil62hrsmx2lhja9fpmm-vips-8.6.4/bin/shrink_width had a zero exit code or showed the expected version
- Warning: no invocation of /nix/store/cffal7h8l17axil62hrsmx2lhja9fpmm-vips-8.6.4/bin/batch_image_convert had a zero exit code or showed the expected version
- Warning: no invocation of /nix/store/cffal7h8l17axil62hrsmx2lhja9fpmm-vips-8.6.4/bin/batch_rubber_sheet had a zero exit code or showed the expected version
- Warning: no invocation of /nix/store/cffal7h8l17axil62hrsmx2lhja9fpmm-vips-8.6.4/bin/batch_crop had a zero exit code or showed the expected version
- Warning: no invocation of /nix/store/cffal7h8l17axil62hrsmx2lhja9fpmm-vips-8.6.4/bin/vipsprofile had a zero exit code or showed the expected version
- /nix/store/cffal7h8l17axil62hrsmx2lhja9fpmm-vips-8.6.4/bin/vips-8.6 passed the binary check.
- 5 of 11 passed binary check by having a zero exit code.
- 0 of 11 passed binary check by having the new version present in output.
- found 8.6.4 with grep in /nix/store/cffal7h8l17axil62hrsmx2lhja9fpmm-vips-8.6.4
- directory tree listing: https://gist.github.com/3d47ce9f75e2a1d701b3089ffa679618
- du listing: https://gist.github.com/b6aa67c89ec9bb55f45e21ae98e82fdc