specify to use semver with buildpack versions in buildpack.toml

[danielleadams]

The specs don't specify the versioning conventions that should be used with buildpacks, even though https://github.com/buildpacks/libbuildpack/blob/b2e4a9ef07aff26c430dfac2fbc928ee4164af35/buildpack/info.go#L27 expects a semver.

We could also include a definition of what types of changes would update the major/minor/patches (or this could go in the docs).

[retrohacker]

https://github.com/buildpacks/spec/blob/master/buildpack.md#build-plan-toml

Came here to ask something similar. Thanks for the link @danielleadams this helps a lot ❤️

Reading the current docs it seems like the "plan" would require each buildpack to do version detection on behalf of it's dependencies, but being able to say 'I need any Node.js runtime semver compatible with the 14 release line' would be powerful.

[nebhale]

@danielleadams I seem to remember that we’d decided on semver syntax, but not semver semantics. Did you plan on submitting a PR to the spec for this?

[danielleadams]

@nebhale Yes, I can do that. However, this will make breaking changes to the spec (even though it won't to the API). Are there other steps I need to take for breaking spec changes besides submitting a pull request?

[nebhale]

No other steps necessary. We'll handle moving it around so that it goes into the appropriate version of the specification to manage the breakage.

[danielleadams]

Cool - I'll make a PR then.

[danielleadams]

Made the pull request here: #85

[ekcasey]

Resolved by 4ddee61