Tweak development.md for more speed (#2667)

Adding the `--progress` flag shows the same output as what `git clone`
would show. This is very nice for slow connections. Without it, the
command may run for many minutes without providing any indication that
it is still doing something.

For `--depth=1`, I think it should be safe as most people have new
enough git versions nowadays, but let's be safe and make it an optional
suggestion. I ran all the tests fine with `--depth=1`, but I don't know
whether things will keep working when the submodules get updated for
systems with old git versions.

docs/development.md

@@ -5,9 +5,12 @@
 ```shell
 git clone https://github.com/llvm/torch-mlir
 cd torch-mlir
-git submodule update --init
+git submodule update --init --progress
 ```
 
+Optionally, use `--depth=1` to make a shallow clone of the submodules.
+While this is running, you can already setup the Python venv and dependencies in the next step.
+
 ## Setup your Python VirtualEnvironment and Dependencies
 
 Also, ensure that you have the appropriate `python-dev` package installed