Different release naming

[kosciCZ]

So we've encoutered an issue when some projects don't name their releases by just version number, but with a 'v' prefix or something else. I don't think there's a need to support them all, but we need to takes this into account, because the bot just fails when it tries to get the previous version and it's not in expected format.

$ docker run meta-test-family-bot ---> Setting up ssh key... Agent pid 12 Identity added: ./.ssh/id_rsa (./.ssh/id_rsa) 11:33:17.992 configuration.py DEBUG Loaded configuration for fedora-modularity/meta-test-family 11:33:17.993 releasebot.py INFO release-bot v0.4.1 reporting for duty! 11:33:17.993 github.py DEBUG Fetching release-conf.yaml 11:33:33.903 releasebot.py DEBUG No merged release PR found 11:33:37.261 releasebot.py DEBUG No more open issues found 11:33:37.261 releasebot.py DEBUG Done. Going to sleep for 300s 11:38:37.361 github.py DEBUG Fetching release-conf.yaml 11:38:52.759 releasebot.py DEBUG No merged release PR found 11:38:53.323 releasebot.py INFO Found new release issue with version: 0.8.4 11:38:56.695 releasebot.py DEBUG No more open issues found Traceback (most recent call last): File "/opt/app-root/src/.local/bin/release-bot", line 11, in sys.exit(main()) File "/opt/app-root/src/.local/lib/python3.6/site-packages/release_bot/releasebot.py", line 276, in main rb.run() File "/opt/app-root/src/.local/lib/python3.6/site-packages/release_bot/releasebot.py", line 261, in run self.make_release_pull_request() File "/opt/app-root/src/.local/lib/python3.6/site-packages/release_bot/releasebot.py", line 155, in make_release_pull_request if Version.coerce(prev_version) >= Version.coerce(self.new_pr['version']): File "/opt/app-root/src/.local/lib/python3.6/site-packages/semantic_version/base.py", line 140, in coerce % version_string ValueError: Version string lacks a numerical component: 'Release 0.8.3'

Also, it should be stated in a readme, that releases need to be in this format too, not just the PRs.