Fixed commit message.

@whitequark thanks for proposing this PR. Please add a test (or perhaps a simple wasip1 step/workflow) to ensure that this works and future changes won't break it?

Please add a test (or perhaps a simple wasip1 step/workflow) to ensure that this works and future changes won't break it?

I've considered it but I could not find a place where e.g. GOOS=js would be tested, or other existing OSes. Did I miss it?

@whitequark Let's create a new GH workflow just for this, that installs wasmtime and run a simple test that confirm some basic workflow for wasm. For example:

$ curl https://wasmtime.dev/install.sh -sSf | bash
$ GOOS=wasip1 GOARCH=wasm go test -c -o go-git.wasm github.com/go-git/go-git/v6
$ wasmtime run go-git.wasm -test.v -test.run '^TestWasmInit$' github.com/go-git/go-git/v6
=== RUN   TestWasmInit
--- PASS: TestWasmInit (0.00s)
PASS

The test could be something as simple as:

func TestWasmInit(t *testing.T) {
	st := memory.NewStorage()
	wt := memfs.New()

	r, err := Init(st, WithWorkTree(wt))
	require.NoError(t, err)
	assert.NotNil(t, r)

	h := createCommit(t, r)
	assert.False(t, h.IsZero())

	ref, err := r.Head()
	require.NoError(t, err)
	require.NotNil(t, ref)
	assert.False(t, ref.Hash().IsZero())
	assert.Equal(t, h, ref.Hash())
}

But feel free to expand on it.

Also, please note that this PR also needs an additional change:

func preReceiveHook(_ string) []byte {
	return []byte{}
}