Error in re-building vignettes:
  ...
Fontconfig error: "/Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/magick/etc/fonts/conf.d/65-nonlatin.conf", line 6: invalid attribute 'version'
Fontconfig warning: "/Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/magick/etc/fonts/conf.d/65-nonlatin.conf", line 8: unknown element "description"
Fontconfig warning: "/Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/magick/etc/fonts/conf.d/69-unifont.conf", line 4: unknown element "its:rules"
Fontconfig warning: "/Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/magick/etc/fonts/conf.d/69-unifont.conf", line 5: unknown element "its:translateRule"
Fontconfig error: "/Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/magick/etc/fonts/conf.d/69-unifont.conf", line 5: invalid attribute 'translate'
Fontconfig error: "/Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/magick/etc/fonts/conf.d/69-unifont.conf", line 5: invalid attribute 'selector'
Fontconfig error: "/Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/magick/etc/fonts/conf.d/69-unifont.conf", line 6: invalid attribute 'xmlns:its'
Fontconfig error: "/Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/magick/etc/fonts/conf.d/69-unifont.conf", line 6: invalid attribute 'version'
Fontconfig warning: "/Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/magick/etc/fonts/conf.d/80-delicious.conf", line 4: unknown element "its:rules"
Fontconfig warning: "/Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/magick/etc/fonts/conf.d/80-delicious.conf", line 5: unknown element "its:translateRule"
Fontconfig error: "/Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/magick/etc/fonts/conf.d/80-delicious.conf", line 5: invalid attribute 'translate'
Fontconfig error: "/Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/magick/etc/fonts/conf.d/80-delicious.conf", line 5: invalid attribute 'selector'
Fontconfig error: "/Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/magick/etc/fonts/conf.d/80-delicious.conf", line 6: invalid attribute 'xmlns:its'
Fontconfig error: "/Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/magick/etc/fonts/conf.d/80-delicious.conf", line 6: invalid attribute 'version'
Fontconfig warning: "/Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/magick/etc/fonts/conf.d/90-synthetic.conf", line 4: unknown element "its:rules"
Fontconfig warning: "/Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/magick/etc/fonts/conf.d/90-synthetic.conf", line 5: unknown element "its:translateRule"
Fontconfig error: "/Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/magick/etc/fonts/conf.d/90-synthetic.conf", line 5: invalid attribute 'translate'
Fontconfig error: "/Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/magick/etc/fonts/conf.d/90-synthetic.conf", line 5: invalid attribute 'selector'
Fontconfig error: "/Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/magick/etc/fonts/conf.d/90-synthetic.conf", line 6: invalid attribute 'xmlns:its'
Fontconfig error: "/Volumes/SSD-Data/Builds/R-dev-web/QA/Simon/packages/el-capitan-x86_64/Rlib/3.5/magick/etc/fonts/conf.d/90-synthetic.conf", line 6: invalid attribute 'version'
Fontconfig error: Cannot load default config file
Quitting from lines 60-71 (clinreport_modify_outputs.Rmd) 
Error: processing vignette 'clinreport_modify_outputs.Rmd' failed with diagnostics:
`render_flextable` needs to be used as a renderer for a knitr/rmarkdown R code chunk (render by rmarkdown)
Execution halted