ci: add goreleaser settings

[supercaracal]

I'd say that it would be better to use tools instead of manual upload for distribution of built files.

Since fanlin depends on WebP library for Golang, it seems that we can't disable cgo. Also, in GitHub Actions, it looks difficult to do cross-compiling to Windows, macOS and ARM architectures on the latest Ubuntu machine if cgo enabled.

• Cross Compile fails with WebP support. #33

Please let me know if there are overlooking somethings. I'm not familiar with WebP. But I think it's OK if the following test case is passed in CI.

fanlin/lib/image/image_test.go

Lines 130 to 168 in 6a75afc

	func TestEncodeWebP(t *testing.T) {
	// Lossless
	img, _ := DecodeImage(webpLosslessBin)
	webpLosslessBin.Seek(0, 0)
	if format := img.GetFormat(); format != "webp" {
	t.Fatalf("format is %v, expected webp", format)
	}
	bin, err := EncodeWebP(img.GetImg(), -1, true)
	if err != nil {
	t.Fatalf("err is %v.", err)
	}
	if bin == nil {
	t.Fatalf("bin is nil.")
	}
	// Lossy
	img, _ = DecodeImage(webpLossyBin)
	webpLossyBin.Seek(0, 0)
	if format := img.GetFormat(); format != "webp" {
	t.Fatalf("format is %v, expected webp", format)
	}
	bin, err = EncodeWebP(img.GetImg(), -1, false)
	if err != nil {
	t.Fatalf("err is %v.", err)
	}
	if bin == nil {
	t.Fatalf("bin is nil.")
	}
	// error
	img, _ = DecodeImage(confBin)
	confBin.Seek(0, 0)
	_, err = EncodeWebP(img.GetImg(), 50, true)
	if err == nil {
	t.Fatalf("err is %v.", err)
	}
	}