skip getReleases function if version is provided

[gugu]

Github API needs to be called only to get the latest version, but getReleases is called every time. It would be great to have ability skip API request with rate limit without providing GITHUB_TOKEN and provide version instead

[2bndy5]

This may only be applicable if the full version spec (major, minor, patch) is specified. Otherwise, the GH project that tags the desired releases would need to have rolling tags (v1 for any new v1.x release, v1.5 for any new v1.5.x release, etc).