fix: update breaking changes in v3

colorscheme.lua

@@ -1,2 +1,2 @@
 -- Set colorscheme to use
-return "astronvim"
+return "astrodark"

heirline/colors.lua

@@ -1,5 +1,6 @@
 -- Customize colors for each element each element has a `_fg` and a `_bg`
 return function(colors)
-  colors.git_branch_fg = astronvim.get_hlgroup("Conditional").fg
+  local get_hlgroup = require("astronvim.utils").get_hlgroup
+  colors.git_branch_fg = get_hlgroup("Conditional").fg
   return colors
 end