PEP440 version identification about esmvaltool

[bouweandela]

In that case we will use the following version names for version 2.0:

2.0a0   # First alpha release
2.0b0   # First beta release
2.0     # Final version 2.0 release

In case we need multiple alpha or beta releases for version 2.0, the number behind the a/b will be incremented

[mattiarighi]

We had a short discussion and decided to go for PEP440.

@ESMValGroup/esmvaltool-coreteam

@bouweandela , feel free to update the project names and close this.

[bjoernbroetz]

So, then this will be closed.

[bouweandela]

We need a decision on this for the upcoming pre version 2 releases. For now I've used semantic versioning (i.e. with an -alpha and -beta suffix) for the projects, but this can of course easily be changed to something PEP440 compatible if that is preferred.
I'm not sure if using a tool like versioneer adds much to this project, as there are very few releases so far.

[bjlittle]

@bouweandela I'm also not particularly fussed about versioneer, just thought I'd ask... but it was sooo long ago, I can't recall even asking 😉

With regards to PEP440 vs semantic... I don't think that there are any restrictions with regards to whether conda or PyPI (or other packaging tools that we care about?) can parse both version formats.

We've recently moved from semantic to PEP440, so if we're having a vote, I'd opt for PEP440 as a standard.

But I agree with @bouweandela. The core devs should make a call on this asap.