print/ruby-pdf-reader: update to 2.6.0

2.6.0 (2021-11-12)

* Text extraction improvements

  - Improved text layout on pages with a variety of font sizes
    (http://github.com/yob/pdf-reader/pull/355)
  - Fixed text positioning for some rotated pages
    (http://github.com/yob/pdf-reader/pull/356)
  - Improved character width calculation for PDFs using built-in
    (non-embedded) ZapfDingbats (http://github.com/yob/pdf-reader/pull/373)
  - Skip zero-width characters (http://github.com/yob/pdf-reader/pull/372)

* Performance improvements

  - Reduced memory pressure when decoding TIFF images
    (http://github.com/yob/pdf-reader/pull/360)
  - Optional dependency on ascii81_native gem for faster processing of files
    using the ascii85 filter (http://github.com/yob/pdf-reader/pull/359)

* Successfully parse more files

  - Gracefully handle some non-spec compliant CR/LF issues
    (http://github.com/yob/pdf-reader/pull/364)
  - Fix parsing of some escape sequences in content streams
    (http://github.com/yob/pdf-reader/pull/368)
  - Increase the amount of junk bytes we detect and skip at the end of a
    file (382)
  - Ignore "/Prev 0" in trailers (http://github.com/yob/pdf-reader/pull/383)
  - Fix parsing of some inline images (BI ID EI tokens)
    (http://github.com/yob/pdf-reader/pull/389)
  - Gracefully handle some xref tables that incorrectly start with 1
    (http://github.com/yob/pdf-reader/pull/384)

(taca)