Tweak file icons (#4145)

YML icon should be purple, and folder icon should be grey

- **PR Description**

- **Please check if the PR fulfills these requirements**

* [ ] Cheatsheets are up-to-date (run `go generate ./...`)
* [ ] Code has been formatted (see
[here](https://github.com/jesseduffield/lazygit/blob/master/CONTRIBUTING.md#code-formatting))
* [ ] Tests have been added/updated (see
[here](https://github.com/jesseduffield/lazygit/blob/master/pkg/integration/README.md)
for the integration test guide)
* [ ] Text is internationalised (see
[here](https://github.com/jesseduffield/lazygit/blob/master/CONTRIBUTING.md#internationalisation))
* [ ] If a new UserConfig entry was added, make sure it can be
hot-reloaded (see
[here](https://github.com/jesseduffield/lazygit/blob/master/docs/dev/Codebase_Guide.md#using-userconfig))
* [ ] Docs have been updated if necessary
* [ ] You've read through your own file changes for silly mistakes etc

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pkg/gui/presentation/icons/file_icons.go

@@ -10,9 +10,9 @@ import (
 // https://github.com/nvim-tree/nvim-web-devicons/blob/master/lua/nvim-web-devicons/icons-default.lua
 
 var (
-	DEFAULT_FILE_ICON      = IconProperties{Icon: "\uf15b", Color: "#ECECEC"}     // 
+	DEFAULT_FILE_ICON      = IconProperties{Icon: "\uf15b", Color: "#878787"}     // 
 	DEFAULT_SUBMODULE_ICON = IconProperties{Icon: "\U000f02a2", Color: "#FF4F00"} // 󰊢
-	DEFAULT_DIRECTORY_ICON = IconProperties{Icon: "\uf07b", Color: "#0087FF"}     // 
+	DEFAULT_DIRECTORY_ICON = IconProperties{Icon: "\uf07b", Color: "#878787"}     // 
 )
 
 var nameIconMap = map[string]IconProperties{
@@ -742,8 +742,8 @@ var extIconMap = map[string]IconProperties{
 	".xpi":            {Icon: "\ueae6", Color: "#375A8E"},     // 
 	".xul":            {Icon: "\uf121", Color: "#DC682E"},     // 
 	".xz":             {Icon: "\uf410", Color: "#ECA517"},     // 
-	".yaml":           {Icon: "\ue6a8", Color: "#C90F02"},     // 
-	".yml":            {Icon: "\ue6a8", Color: "#C90F02"},     // 
+	".yaml":           {Icon: "\ue6a8", Color: "#a074b3"},     // 
+	".yml":            {Icon: "\ue6a8", Color: "#a074b3"},     // 
 	".zig":            {Icon: "\ue6a9", Color: "#FAA825"},     // 
 	".zip":            {Icon: "\uf410", Color: "#ECA517"},     // 
 	".zsh":            {Icon: "\U000f018d", Color: "#FF7043"}, // 󰆍