Reported rule URLs refer to `develop` branch instead of corresponding tagged release

### Description

In the generated YAML report, the rule URL refers to the `develop` branch instead of the tagged release if used from a release.

### How To Reproduce

Running `scancode -l --license-text setup.py --info --url --copyright --yaml setup.yaml` on a file generates a YAML report which includes

```yaml
rule_url: https://github.com/nexB/scancode-toolkit/tree/develop/src/licensedcode/data/rules/apache-2.0_1251.RULE
```

This is misleading as the rule might have changed when the report has been generated with an older ScanCode Toolkit version or even deleted, thus making the reference more or less obsolete/fragile.

### System configuration

* What OS are you running on? Linux
* What version of scancode-toolkit was used to generate the scan file? 32.1.0
* What installation method was used to install/run scancode? pip