Bump Asciidoctor-PDF version to 2.3.9

[asciidoctor-updateclibot[bot]]

Bump Asciidoctor-PDF version

Update the key ASCIIDOCTOR_PDF_VERSION in the test harness

Updated to content "ASCIIDOCTOR_PDF_VERSION=2.3.9" in file "tests/asciidoctor.bats"

2.3.9

Release published on the 2023-06-28 22:00:21 +0000 UTC at the url https://github.com/asciidoctor/asciidoctor-pdf/releases/tag/v2.3.9

This is a patch release in the 2.3.x release line that fixes alignment of image blocks in the multi-column layout and preserves the bottom end placement of the caption on a table when the unbreakable or breakable option is set.

## Distribution

- [RubyGem (asciidoctor-pdf)](https://rubygems.org/gems/asciidoctor-pdf)

## Changelog

### Bug Fixes

* correctly align block image in raster format in column when align is right or center and page columns are enabled (#2433)
* honor table caption end placement (`table-caption-end` theme key) when `unbreakable` (or `breakable`) option is set on table (#2434)

## Release meta

Released on: 2023-06-28
Released by: @mojavelinux
Release beer: Pappy Legma by Goat Patch Brewing Company

Logs: [resolved issues](https://github.com/asciidoctor/asciidoctor-pdf/issues?q=is%3Aissue+label%3Av2.3.9+is%3Aclosed) | [source diff](https://github.com/asciidoctor/asciidoctor-pdf/compare/v2.3.8...v2.3.9) | [gem diff](https://my.diffend.io/gems/asciidoctor/v2.3.8/v2.3.9)

## Credits

A very special thanks to all the **awesome** [supporters of the Asciidoctor OpenCollective campaign](https://opencollective.com/asciidoctor), who provide critical funding for the ongoing development of this project.

Update the key ASCIIDOCTOR_PDF_VERSION in the README.adoc file

Updated to content ":ASCIIDOCTOR_PDF_VERSION: 2.3.9" in file "README.adoc"

2.3.9

Release published on the 2023-06-28 22:00:21 +0000 UTC at the url https://github.com/asciidoctor/asciidoctor-pdf/releases/tag/v2.3.9

This is a patch release in the 2.3.x release line that fixes alignment of image blocks in the multi-column layout and preserves the bottom end placement of the caption on a table when the unbreakable or breakable option is set.

## Distribution

- [RubyGem (asciidoctor-pdf)](https://rubygems.org/gems/asciidoctor-pdf)

## Changelog

### Bug Fixes

* correctly align block image in raster format in column when align is right or center and page columns are enabled (#2433)
* honor table caption end placement (`table-caption-end` theme key) when `unbreakable` (or `breakable`) option is set on table (#2434)

## Release meta

Released on: 2023-06-28
Released by: @mojavelinux
Release beer: Pappy Legma by Goat Patch Brewing Company

Logs: [resolved issues](https://github.com/asciidoctor/asciidoctor-pdf/issues?q=is%3Aissue+label%3Av2.3.9+is%3Aclosed) | [source diff](https://github.com/asciidoctor/asciidoctor-pdf/compare/v2.3.8...v2.3.9) | [gem diff](https://my.diffend.io/gems/asciidoctor/v2.3.8/v2.3.9)

## Credits

A very special thanks to all the **awesome** [supporters of the Asciidoctor OpenCollective campaign](https://opencollective.com/asciidoctor), who provide critical funding for the ongoing development of this project.

Update the value of ARG asciidoctor_pdf_version in the Dockerfile

changed lines [16] of file "/tmp/updatecli/github/asciidoctor/docker-asciidoctor/Dockerfile"

2.3.9

Release published on the 2023-06-28 22:00:21 +0000 UTC at the url https://github.com/asciidoctor/asciidoctor-pdf/releases/tag/v2.3.9

This is a patch release in the 2.3.x release line that fixes alignment of image blocks in the multi-column layout and preserves the bottom end placement of the caption on a table when the unbreakable or breakable option is set.

## Distribution

- [RubyGem (asciidoctor-pdf)](https://rubygems.org/gems/asciidoctor-pdf)

## Changelog

### Bug Fixes

* correctly align block image in raster format in column when align is right or center and page columns are enabled (#2433)
* honor table caption end placement (`table-caption-end` theme key) when `unbreakable` (or `breakable`) option is set on table (#2434)

## Release meta

Released on: 2023-06-28
Released by: @mojavelinux
Release beer: Pappy Legma by Goat Patch Brewing Company

Logs: [resolved issues](https://github.com/asciidoctor/asciidoctor-pdf/issues?q=is%3Aissue+label%3Av2.3.9+is%3Aclosed) | [source diff](https://github.com/asciidoctor/asciidoctor-pdf/compare/v2.3.8...v2.3.9) | [gem diff](https://my.diffend.io/gems/asciidoctor/v2.3.8/v2.3.9)

## Credits

A very special thanks to all the **awesome** [supporters of the Asciidoctor OpenCollective campaign](https://opencollective.com/asciidoctor), who provide critical funding for the ongoing development of this project.

---

Created automatically by Updatecli Options: Most of Updatecli configuration is done via its manifest(s). If you close this pull request, Updatecli will automatically reopen it, the next time it runs. If you close this pull request and delete the base branch, Updatecli will automatically recreate it, erasing all previous commits made. Feel free to report any issues at github.com/updatecli/updatecli. If you find this tool useful, do not hesitate to star our GitHub repository as a sign of appreciation, and/or to tell us directly on our chat!