Use the correct git tag version when building from master branch.

[orsenthil]

What type of PR is this?

Which issue does this PR fix?:

The master branch pointed to a old tag, so all the latest commits were pushed to these tags v1.12.0-418-g612e8177 with prefix v1.12.0-

commit 612e81771c5641b0a58b37d9727526721f01e21a (HEAD -> master, origin/master, origin/HEAD, ref)
Author: Senthil Kumaran <[email protected]>
Date:   Fri Oct 18 12:06:51 2024 -0700

    Update Limits and Add New Instance Types. (#3077)
[ec2-user@ip-172-32-32-162 amazon-vpc-cni-k8s]$ git describe --tags --always --dirty
v1.12.0-418-g612e8177

It will be better to use the master as prefix, with this change the tag will now look like

amazon/amazon-k8s-cni:master-612e8177

Testing

[ec2-user@ip-172-32-32-162 amazon-vpc-cni-k8s]$ make docker
docker build --build-arg golang_image="public.ecr.aws/eks-distro-build-tooling/golang:1.22.5-gcc-al2" --build-arg base_image="public.ecr.aws/eks-distro-build-tooling/eks-distro-minimal-base-iptables:latest.2" --network=host  \
        -f scripts/dockerfiles/Dockerfile.release \
        -t "amazon/amazon-k8s-cni:master-612e8177" \