Function version

pub fn version<P: AsRef<Path>>(
    datadir: P,
) -> Result<Option<PartialVersion>, ClusterError>

Yields the version of PostgreSQL required to use a cluster.

This returns the version from the file named PG_VERSION in the data directory if it exists, otherwise this returns None. For PostgreSQL versions before 10 this is typically (maybe always) the major and point version, e.g. 9.4 rather than 9.4.26. For version 10 and above it appears to be just the major number, e.g. 14 rather than 14.2.