Fix release-job.sh version var

Fix release-job.sh version var

Allow only semantic release versions like
"v${SEMVER}" or "${SEMVER}".
Fail the script if the version is not valid.
Do not append any additional characters to the
release version during tagging and pushing steps.

In this case, if the user wants to use the prefixed
"v", they can define it in the releases/*.yaml as:
version: 'v1.0.0'

Issue: RELENG-2131
Change-Id: I71f32600d3e17ec117776be6764c2e45ee934bdd
Signed-off-by: Jessica Wagantall <jwagantall@linuxfoundation.org>