feat: add .dockerignore icon

[A-caibird]

add icon for .dockerignore extension

[gegoune]

Thanks!
Please follow https://github.com/nvim-tree/nvim-web-devicons/blob/master/CONTRIBUTING.md guide. Namely run make to generate light background icons and fix formatting.

[A-caibird]

@gegoune I have already completed it.

[gegoune]

I see we already have support for .dockerignore file provided based on filename rather than extension:

$ rg dockerignore
lua/nvim-web-devicons/light/icons_by_filename.lua
12:  [".dockerignore"]              = { icon = "󰡨", color = "#2E5F99", cterm_color = "25",  name = "Dockerfile"              },

lua/nvim-web-devicons/default/icons_by_filename.lua
12:  [".dockerignore"]              = { icon = "󰡨", color = "#458EE6", cterm_color = "68",  name = "Dockerfile"              },

Do we need both? Which one should we keep?

[A-caibird]

@gegoune yes，I think all of them are necessary.such as，dev.dockerignore and product.dockerignore

[gegoune]

TIL https://docs.docker.com/build/concepts/context/#dockerignore-files

Thanks!