docs: add NEWS item

NEWS.md

 # xaringanthemer (development version)
 
-<!-- NEWS.md is maintained by https://cynkra.github.io/fledge, do not edit -->
+- Update the spelling of `colour` for compatibility with ggplot2 >= 3.5.1 (@teunbrand #79).
 
 # xaringanthemer 0.4.2
 
 
 # xaringanthemer 0.4.1
 
-* Text alignment in code blocks in `left`, `center`, or `right` aligned slides 
+* Text alignment in code blocks in `left`, `center`, or `right` aligned slides
   no longer matches the slide text. Instead, the code block width is reduced,
   if possible, and the block is pushed to the left, center, or right using
   margins (#68).
-  
+
 * The style functions are now more permissive about color names in the `color`
   argument. Color names should be valid CSS classes that can also be used as CSS
   variable names, but the `style_` function only stops with an error if the
   color name contains spaces. (@jdlom #69)
-  
+
 * Fixed an issue that caused problems rendering the xaringanthemer R Markdown
   template if the showtext package isn't installed (thanks @beatrizmilz, #65).
 
 * Added `text_bold_font_weight` argument to xaringanthemer style functions with
   a corresponding CSS rule setting the `font-weight` property of `<strong>`
   elements (thanks @matiasandina, #50).
- 
+
 * The style functions gain a `link_decoration` argument to set the
   [`text-decoration`](https://developer.mozilla.org/en-US/docs/Web/CSS/text-decoration)
   property for links (#57).
-  
+
 * Set slide number font size in `rem` so that increasing the font size at the
   slide level doesn't result in giant slide numbers (#53).
 
 * The xaringanthemer slide skeleton (R Markdown template) will now render when
   packages that are used in the template but not in xaringanthemer's Imports are
   not installed (#52).
-  
+
 * xaringanthemer no longer sets the `fig.showtext` chunk option when the
-  showtext package isn't installed and also when `fig.showtext = FALSE` 
+  showtext package isn't installed and also when `fig.showtext = FALSE`
   (thanks @mikedecr #36, #56).
 
 # xaringanthemes 0.3.4
 
 * Add `header_font_family_fallback` to control fallback fonts for headings
   (thanks @mattwarkentin, #41)
-  
+
 * New xaringanthemer presentation skeleton with a kitchen sink of typical
   slide elements with the goal of making it easier to preview new themes
   during development.
 # xaringanthemer 0.3.0
 
 * Adds `theme_xaringan()`, a ggplot2 theme that automatically uses the colors
-  and font styles of your xaringanthemer style. Also adds 
-  `scale_xaringan_discrete()` and `scale_xaringan_continuous()` functions that 
+  and font styles of your xaringanthemer style. Also adds
+  `scale_xaringan_discrete()` and `scale_xaringan_continuous()` functions that
   use your slides' primary colors for the color or fill aesthetics. These theme
   functions can recover the primary colors used in a xaringanthemer (>= 0.3.0)
   CSS file even if you don't call the style function directly in your slides.
   `inverse`, `center`, `middle`, or `bottom`-styled slides. When disabled,
   you can still enable slide title headers by adding the `header_background`
   class to a slide. (thanks, @Btibert3, #10)
-  
+
 * The underlying template now uses the `whisker` package.
 
-* xaringanthemer styles now use CSS variables throughout. Most of the settings 
+* xaringanthemer styles now use CSS variables throughout. Most of the settings
   used in defining a style are stored in CSS variables. The variable names are
   documented in their corresponding arguments. For example, the color selected
   for `background_color` is stored in the variable `--background-color`. These
   fonts. The new defaults use [Cabin](https://fonts.google.com/specimen/Cabin)
   for headings and [Noto Sans](https://fonts.google.com/specimen/Noto+Sans) for
   body text. These fonts are easier to read on screens and at a distance during
-  presentations, and they support a wide variety of languages and weights. 
-  Another reason for the change is that the xaringan (remarkjs) default body 
+  presentations, and they support a wide variety of languages and weights.
+  Another reason for the change is that the xaringan (remarkjs) default body
   font, _Droid Serif_, is no longer officially included in Google Fonts.
-  
+
 * Additional colors can be provided in the `colors` argument, which takes a
   named vector of colors. The names become both CSS classes and CSS variables
   that can be used throughout your slide styles. For example,
-  `colors = c(red = "#d34213")` creates a `.red` CSS class for red foreground 
+  `colors = c(red = "#d34213")` creates a `.red` CSS class for red foreground
   text, a `.bg-red` CSS class for a red background, and a `--red` CSS variable
   that can be referenced as `var(--red)` in any `_color` argument of your style
   function.
 
 * Better handling of multiple `extra_fonts`, including improved error messages.
   (Thanks @pat-s, #19).
-  
+
 * `style_extra_css()` (previously `write_extra_css()`) gained an `append`
   argument so that it can append to or overwrite an existing file (thanks @pat-s, #17).
 
-* The underlying tibble holding the theme template variables was updated to 
+* The underlying tibble holding the theme template variables was updated to
   work with `tibble 3.0.0` (thanks @techisdead, @SymbolixAU, #32).
-  
+
 * The `css-help` vignette was removed and may be re-written in the future.
 
 * Style function arguments that accept CSS property values are now documented in