all: replace empty slice literal with var (#8990)

refactor: replace empty slice literal with `var`

An empty slice can be represented by `nil` or an empty slice literal. They are
functionally equivalent — their `len` and `cap` are both zero — but the `nil`
slice is the preferred style. For more information about empty slices,
see [Declaring Empty Slices](https://github.com/golang/go/wiki/CodeReviewComments#declaring-empty-slices).

Co-authored-by: deepsource-autofix[bot] <62050782+deepsource-autofix[bot]@users.noreply.github.com>

lib/versioner/empty_dir_tracker.go

@@ -32,7 +32,8 @@ func (t emptyDirTracker) addFile(path string) {
 }
 
 func (t emptyDirTracker) emptyDirs() []string {
-	empty := []string{}
+	var empty []string
+
 	for dir := range t {
 		empty = append(empty, dir)
 	}

lib/versioner/external.go

@@ -90,7 +90,8 @@ func (v external) Archive(filePath string) error {
 	cmd := exec.Command(words[0], words[1:]...)
 	env := os.Environ()
 	// filter STGUIAUTH and STGUIAPIKEY from environment variables
-	filteredEnv := []string{}
+	var filteredEnv []string
+
 	for _, x := range env {
 		if !strings.HasPrefix(x, "STGUIAUTH=") && !strings.HasPrefix(x, "STGUIAPIKEY=") {
 			filteredEnv = append(filteredEnv, x)