Add Lazy, a Neovim plugin manager (#326)

* fix upgrade order of (n)vim plugins

* treesitter should use the synchronous cmd

* add lazy pkg manager for neovim

* fix lazy cmd

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Co-authored-by: Thomas Schönauer <37108907+DottoDev@users.noreply.github.com>

src/steps/upgrade.vim

@@ -33,6 +33,11 @@ if exists(":PaqUpdate")
     PaqUpdate
 endif
 
+if exists(":Lazy")
+    echo "Lazy Update"
+    +Lazy! sync
+endif
+
 function! UpdateCoCAndTS()
     if exists(":CocUpdateSync")
         echo "CocUpdateSync"