Close client connection when done.

This will take care of cleaning all the lingering connections that would have been left open which would eventually trigger a too many files error or an OOM.

internal/pihole/client.go

@@ -201,6 +201,7 @@ func (c *Client) getStatistics() (*Stats, error) {
 		return nil, fmt.Errorf("an error has occured during retrieving PI-Hole statistics: %w", err)
 	}
 
+	defer resp.Body.Close()
 	body, err := ioutil.ReadAll(resp.Body)
 	if err != nil {
 		return nil, fmt.Errorf("unable to read PI-Hole statistics HTTP response: %w", err)