lower version, for example 2.6.8
```properties
dubbo.provider.version=1.0
```

2.7.6 failed to recognize the provider url with 'default.version=1.0' key,  it only takes 'version.1.0' into consideration.

for (Map.Entry<String, String> entry : parameters.entrySet()) {
            String value = getParameters().get(entry.getKey());
            if (value == null) {
                if (entry.getValue() != null) {
                    hasAndEqual = false;
                    break;
                }
            } else {
                if (!value.equals(entry.getValue())) {
                    hasAndEqual = false;
                    break;
                }
            }
        }
        
        if (hasAndEqual) {
            return this;
        }
        Map<String, String> map = new HashMap<>(getParameters());
        map.putAll(parameters);
        return new URL(protocol, username, password, host, port, path, map);
    }
    public URL addParametersIfAbsent(Map<String, String> parameters) {
        if (CollectionUtils.isEmptyMap(parameters)) {
            return this;
        }
        Map<String, String> map = new HashMap<>(parameters);
        map.putAll(getParameters());
        return new URL(protocol, username, password, host, port, path, map);
    }