anchor.diff:  * add Ruby 3.1 to CI matrix; use as primary Ruby
   * test against Asciidoctor upstream (#1821)
   * skip tests for unreadable files when euid is 0
  -* test against pygments.rb 2.0.0
  +
  +== 1.6.1 (2021-09-04) - @mojavelinux
  +
  +Enhancements::
  +
  +* align footnotes block to the bottom of the page it is placed on (#1833)
  +
  +Bug Fixes::
  +
  +* patch Prawn to preserve leading null character when running on Ruby 3; preserves inline anchors when text is split by page (#1963)
  +
  +== 1.6.0 (2021-05-10) - @mojavelinux
  +
  +Enhancements::
  +
  +* allow path of ghostscript command to be controlled using `GS` env var (#1791)
  +
  +Bug Fixes::
  +
  +* do not hyphenate a hyphen when hyphenation is enabled (#1562)
  +
  +Compliance::
  +
  +* add support for Ruby 3 and drop support for Ruby < 2.5 and JRuby < 9.2 (#1681)
  +* upgrade to Prawn 2.4.0 (adds support for Ruby 3 and OTF font support)
  +* upgrade to prawn-svg 0.32 (adds support for Ruby 3 without a patch and for loading embedded images from a data URI)
  +* upgrade to prawn-icon 3.0.x
  +* release lock on ttfunk version (1.6 produces slightly different output from 1.5 for certain missing glyphs)
  +* drop support for Asciidoctor < 2 (#1552)
  +
  +Build / Infrastructure::
  +
  +* run tests against pygments.rb 2.x in addition to pygments.rb 1.2.0
   
   == 1.5.3 (2020-02-28) - @mojavelinux
   
  
positive.code: 
  Compliance::
  
  * drop support for versions of Asciidoctor < 2 (#1552)
  * drop support for Ruby < 2.5 (which includes JRuby 9.1) (#1681)
  * release lock on ttfunk version (1.6 produces slightly different output from 1.5 for certain missing glyphs)
  * upgrade to Prawn 2.3.0 (which adds OTF font support), then to Prawn 2.4.0
  * upgrade to prawn-svg 0.32 (adds support for Ruby 3 without a patch and for loading embedded images from a data URI)
  * upgrade to prawn-icon 3.0.x
  * use YAML.safe_load from Ruby stdlib instead of safe_yaml gem
  * drop deprecated Pdf module alias in API (leaving only PDF)
  * remove deprecated "ascii" fonts; only bundle the more complete "subset" fonts
  
negative.code: * stabilize font paths in built-in themes by prefixing paths with GEM_FONTS_DIR (#1568)
  * assign page-layout attribute in running content so it can be used select background per layout (#1570)
  * reset numbering of footnotes in each chapter; add chapter xreftext to label of footnote reference that refers to previous chapter (#1639)
  * add support for assigning the same font file to all font variants (i.e., styles) using the wildcard key (`*`) (#1588)
  * allow caption max-width to be set to percentage of content by passing argument to fit-content function (#1494)
  * allow theme to control text alignment of caption independent of box alignment (#1493)
  