chore(mini.nvim): use stable version (#346)

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Makefile

@@ -25,7 +25,7 @@ $(addprefix test-, $(TESTFILES)): test-%:
 deps:
 	git clone --depth 1 https://github.com/nvim-lua/plenary.nvim deps/plenary
 	git clone --depth 1 https://github.com/nvim-neotest/nvim-nio deps/nvim-nio
-	git clone --depth 1 https://github.com/echasnovski/mini.nvim deps/mini.nvim
+	git clone --depth 1 https://github.com/echasnovski/mini.nvim deps/mini.nvim --branch stable
 	git clone --depth 1 https://github.com/nvim-treesitter/nvim-treesitter deps/nvim-treesitter
 	git clone --depth 1 https://github.com/nvim-treesitter/playground deps/playground
 	git clone --depth 1 https://github.com/nvim-neotest/neotest deps/neotest