fix: detect helmfile.yaml

Author: eshepelyuk

ftdetect/helm.vim

@@ -1,4 +1,4 @@
-autocmd BufRead,BufNewFile */templates/*.yaml,*/templates/*.tpl,*.gotmpl set ft=helm
+autocmd BufRead,BufNewFile */templates/*.yaml,*/templates/*.tpl,*.gotmpl,helmfile.yaml set ft=helm
 
 " Use {{/* */}} as comments
 autocmd FileType helm setlocal commentstring={{/*\ %s\ */}}