Big refactorization

- reduce complexity
- use better tools to format the code
- add more tests
- and too many things to list here

We are rewriting for V3, so these commits are sometimes big and not
fully detailed. Of course, further work will be more documented.

update/update_test.go

@@ -7,7 +7,6 @@ import (
 )
 
 func TestDownloadLatestRelease(t *testing.T) {
-
 	// Reset the version to test the latest release
 	Version = "0.0.0"
 
@@ -17,15 +16,14 @@ func TestDownloadLatestRelease(t *testing.T) {
 
 	// Now call the CheckLatestVersion function
 	version, assets, err := CheckLatestVersion()
-
 	if err != nil {
-		t.Errorf("Error: %s", err)
+		t.Errorf("Error getting latest version: %s", err)
 	}
 
 	fmt.Println("Version found", version)
 
 	// Touch exe binary
-	f, _ := os.OpenFile(exe, os.O_RDONLY|os.O_CREATE, 0755)
+	f, _ := os.OpenFile(exe, os.O_RDONLY|os.O_CREATE, 0o755)
 	f.Write(nil)
 	f.Close()
 
@@ -48,5 +46,4 @@ func TestAlreadyUpToDate(t *testing.T) {
 	}
 
 	t.Log("Version is already the most recent", version)
-
 }