DRONE_SEMVER

If the git tag is a valid semver string, provides the tag as a semver string.

DRONE_SEMVER=1.2.3-alpha.1

The semver string is also available in the following formats:

DRONE_SEMVER_SHORT=1.2.3
DRONE_SEMVER_PATCH=3
DRONE_SEMVER_MINOR=2
DRONE_SEMVER_MAJOR=1
DRONE_SEMVER_PRERELEASE=alpha.1