Resolve "Improve security by enabling and enforcing more linting rules"

Description

See #242 (closed)

controller/nucleus/errors/errors.go

@@ -12,7 +12,7 @@ type ErrNilClient struct {
 }
 
 func (e *ErrNilClient) Error() string {
-	return fmt.Sprintf("client cannot be nil")
+	return fmt.Sprint("client cannot be nil")
 }
 
 // ErrNil implements the Error interface and is called if a struct is nil.
@@ -20,7 +20,7 @@ type ErrNil struct {
 }
 
 func (e *ErrNil) Error() string {
-	return fmt.Sprintf("struct cannot be nil")
+	return fmt.Sprint("struct cannot be nil")
 }
 
 // ErrAlreadyExists implements the Error interface and is called if a specific ID
@@ -39,7 +39,7 @@ type ErrInvalidUUID struct {
 }
 
 func (e *ErrInvalidUUID) Error() string {
-	return fmt.Sprintf("UUID not valid")
+	return fmt.Sprint("UUID not valid")
 }
 
 // ErrInvalidTypeAssertion implements the Error interface and is called if the
@@ -79,7 +79,7 @@ func (e ErrPathNotFound) Error() string {
 type ErrNotYetImplemented struct{}
 
 func (e ErrNotYetImplemented) Error() string {
-	return fmt.Sprintf("function not yet implemented")
+	return fmt.Sprint("function not yet implemented")
 }
 
 // ErrInvalidParameters implements the Error interface and is called if the wrong