Theme - auy_evolve: Up bufferline fg brightness (#6225)

Currently a bit hard to discern inactive and active buffers in a
brighter environment.

runtime/themes/ayu_evolve.toml

@@ -25,6 +25,8 @@ inherits = 'ayu_dark'
 "ui.cursor.primary.select" = { fg = "dark_gray", bg = "magenta" }
 "ui.cursor.primary.insert" = { fg = "dark_gray", bg = "green" }
 "ui.text.inactive" = "gray"
+"ui.bufferline" = { fg = "light_gray", bg = "background" }
+"ui.bufferline.active" = { fg = "light_gray", bg = "dark_gray" }
 
 [palette]
 background = '#020202'