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.

if (i == 0) {
                    throw new IllegalStateException("url missing protocol: \"" + url + "\"");
                }
                protocol = url.substring(0, i);
                url = url.substring(i + 1);
            }
        }
        i = url.indexOf('/');
        if (i >= 0) {
            path = url.substring(i + 1);
            url = url.substring(0, i);
        }
        i = url.lastIndexOf('@');
        if (i >= 0) {
            username = url.substring(0, i);
            int j = username.indexOf(':');
            if (j >= 0) {
                password = username.substring(j + 1);
                username = username.substring(0, j);
            }
            url = url.substring(i + 1);
        }
        i = url.lastIndexOf(':');
        if (i >= 0 && i < url.length() - 1) {
            if (url.lastIndexOf('%') > i) {
                
                
                
                
            } else {