prepare-submission.sh: Allow non-numeric submissions
prepare-submission.sh: Allow non-numeric submissions

:Release Notes:
Submissions tags can now contain release name, remove the sanity checks
for the format and check previous submission only when current
submission contains only digits.

:Detailed Notes:
Be aware that for submissions included in release branch you usually
need to provide -b parameter as well.

:Testing Performed:
Verified by creating new tag in release branch.

:QA Notes:
No change to image.

:Issues Addressed:
[ES-379] Update prepare-submission.sh for branching conventions
[GF-59660] CCC: Allow the branch to be specified in WEBOS_VERSION

Open-webOS-DCO-1.0-Signed-off-by: Martin Jansa <martin.jansa@lge.com>
Open-webOS-DCO-1.0-Signed-off-by: Susan Montooth <susan.montooth@lge.com>

Originally-reviewed-on: https://g2g.palm.com/4536
Cherry-picked-from-commit: f19b2a00af9255a2f8ccc17447e1f502b8bc3eba
Cherry-picked-from-branch: @acadia

Change-Id: I9674bd7ec505130531137df79a98c4a207e38345

openwebos/meta-webos,Garfonso/meta-webos-ports,nizovn/meta-webos-ports,openwebos/meta-webos,openwebos/meta-webos,Garfonso/meta-webos-ports,openwebos/meta-webos,nizovn/meta-webos-ports