Apparently, the Semantic Versioning specification is being changed from accepting "1.2.3beta" to "1.2.3-beta". Compare
Although the latter is labeled as "rc", it is the one being shown on semver.org by default.
Whatever the plan there may be, the PGXN meta spec should at least explicitly mention and link to spec version v1.0.0 for the time being.
Actually, correction, even Semantic Versioning 1.0.0 uses "1.2.3-beta". So the implementation is based on an even older pre-release. But mentioning the version used by PGXN would still be useful, because some stuff in 2.0.0 will probably not be supported yet.
The issue has cropped up again today in the pgxn group.
As a reference, this is the version of the semver spec both pgxn server and client implement:
(it was advertised as 1.0.0 before going backward to 1.0.0rc3 and getting the dash)
We should either drop reference to semver 1.0 and republish the above as the schema we follow or purge pgxn from packages with the bad version and start adopting one of the semver, which involves changing both the client and the server.
FIxed in pgxn/pgxn-manager@061bf22 and other commits.