Switch from SemVer to CalVer (i.e., adopt CEP-8) #4975
Description
Summary
We wish to follow in conda's footsteps and adopt the same CalVer outlined in CEP-8.
We desire to make this change since the current SemVer has lost most of its meaning (3.26 means what exactly in relation to all previous versions?). We’re already following the deprecation schedule outlined in CEP-9 so our versioning no longer needs to indicate breakage (see CEP-8 for the full reasoning used for conda).
### Notify Downstream Teams
- [x] [Matrix Conda Build Tools Channel](https://matrix.to/#/!zjZSkaZgcvxBwdCKne:matrix.org/$cVXIzhtJvTkLr9cHpXGvO8ntA_2bthMfBCPS0quZ9zU?via=matrix.org&via=mozilla.org)
- [x] Anaconda Packaging Team ([Slack thread](https://anaconda.slack.com/archives/C049N05A2R2/p1701185139492609))
- [ ] Conda-forge
- [ ] Bioconda
- [ ] Others?
- [x] Decide which release the switch will occur (January 2024)
- [ ] Amend CEP-8 to specify that conda-build will adopt the policy