all: use T.TempDir to create temporary test directory (#8280)

This commit replaces `os.MkdirTemp` with `t.TempDir` in tests. The
directory created by `t.TempDir` is automatically removed when the test
and all its subtests complete.

Prior to this commit, temporary directory created using `os.MkdirTemp`
needs to be removed manually by calling `os.RemoveAll`, which is omitted
in some tests. The error handling boilerplate e.g.
	defer func() {
		if err := os.RemoveAll(dir); err != nil {
			t.Fatal(err)
		}
	}
is also tedious, but `t.TempDir` handles this for us nicely.

Reference: https://pkg.go.dev/testing#T.TempDir
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>

lib/versioner/simple_test.go

@@ -8,7 +8,6 @@ package versioner
 
 import (
 	"math"
-	"os"
 	"path/filepath"
 	"testing"
 	"time"
@@ -55,11 +54,7 @@ func TestSimpleVersioningVersionCount(t *testing.T) {
 		t.Skip("Test takes some time, skipping.")
 	}
 
-	dir, err := os.MkdirTemp("", "")
-	//defer os.RemoveAll(dir)
-	if err != nil {
-		t.Error(err)
-	}
+	dir := t.TempDir()
 
 	cfg := config.FolderConfiguration{
 		FilesystemType: fs.FilesystemTypeBasic,