Update plugins.md

docs/plugins.md

@@ -526,6 +526,7 @@ See also plugins in modular minifier [`cssnano`].
 * [`postcss-rem-to-px`] converts `rem` values to `px` values.
 * [`postcss-design-tokens`] provides a function to retrieve design tokens
   expressed in JS or JSON, within CSS.
+* [`postcss-pixel-to-remvw`] converting px to both of rem and vw, also one of them
 
 
 [flexbox bugs]: https://github.com/philipwalton/flexbugs
@@ -926,3 +927,4 @@ See also plugins in modular minifier [`cssnano`].
 [`postcss-prefix-hover`]:                 https://github.com/larsmunkholm/postcss-prefix-hover
 [`postcss-resolve-urls`]:                 https://github.com/bognarlaszlo/postcss-resolve-urls
 [`postcss-design-tokens`]:                https://github.com/jptaranto/postcss-design-tokens
+[`postcss-pixel-to-remvw`]:               https://github.com/ben-lau/postcss-pixel-to-remvw