add semver metadata regex

* supports v1.9.0+stable.0

hack/lib/version.sh

@@ -89,7 +89,7 @@ kube::version::get_version_vars() {
       # Try to match the "git describe" output to a regex to try to extract
       # the "major" and "minor" versions and whether this is the exact tagged
       # version or whether the tree is between two tagged versions.
-      if [[ "${KUBE_GIT_VERSION}" =~ ^v([0-9]+)\.([0-9]+)(\.[0-9]+)?([-].*)?$ ]]; then
+      if [[ "${KUBE_GIT_VERSION}" =~ ^v([0-9]+)\.([0-9]+)(\.[0-9]+)?([-].*)?([+].*)?$ ]]; then
         KUBE_GIT_MAJOR=${BASH_REMATCH[1]}
         KUBE_GIT_MINOR=${BASH_REMATCH[2]}
         if [[ -n "${BASH_REMATCH[4]}" ]]; then