voltha-helm-chart: make test target is non-functional (~release tag check)

https://gerrit.opencord.org/plugins/gitiles/voltha-helm-charts/+/refs/heads/master/Makefile#28

Makefile test target has a few issues:

• tagcollisionreject.sh target is hardcoded, configured to work with a single script version.
• script tagcollisionreject.sh non-existent, the raw.githubusercontent URL returns 404.

%  make test
tagcollisionreject.tmp.sh: FAILED
sha256sum: WARNING: 1 computed checksum did NOT match
make: *** [Makefile:52: tagcollisionreject.sh] Error 1

Refactorable variants of the script can be found here:

• https://github.com/joey-onf/wip/tree/origin/master/VOL-4863