v3.42.10: Code quality fixes

- Remove deprecated io/ioutil
- Fix os.DirEntry.ModTime() usage
- Remove unused fields and variables
- Fix ineffective assignments
- Fix error string formatting

internal/cloud/azure.go

@@ -90,7 +90,7 @@ func NewAzureBackend(cfg *Config) (*AzureBackend, error) {
 			}
 		} else {
 			// Use default Azure credential (managed identity, environment variables, etc.)
-			return nil, fmt.Errorf("Azure authentication requires account name and key, or use AZURE_STORAGE_CONNECTION_STRING environment variable")
+			return nil, fmt.Errorf("azure authentication requires account name and key, or use AZURE_STORAGE_CONNECTION_STRING environment variable")
 		}
 	}