Add missing .grid-flow-dense utility (#8193)

Author: hacknug

src/corePlugins.js

@@ -884,6 +884,7 @@ export let corePlugins = {
     addUtilities({
       '.grid-flow-row': { gridAutoFlow: 'row' },
       '.grid-flow-col': { gridAutoFlow: 'column' },
+      '.grid-flow-dense': { gridAutoFlow: 'dense' },
       '.grid-flow-row-dense': { gridAutoFlow: 'row dense' },
       '.grid-flow-col-dense': { gridAutoFlow: 'column dense' },
     })