parametrize tempalte to use `OCP_VER` user have provided

[pthangad]

• Seems we need to add one more feature to parametrize -p TEMPLATE="private-templates/functionality-testing/aos-4_9/ipi-on-osp/versioned-installer" value, as we need to choose right template to specific ocp_version user provides
• we might need an regex to parse user input and prepare value to template.
  eg: template_version = os.getenv("OCP_VER").split('-')[1].replace(".","-")

tkn pipeline start flexy-install \
		-n devtools-gitops \
		-p CLUSTER_NAME="$(NAME)" \
		-p OPENSHIFT_VERSION="$(OCP_VER)" \
		-p TEMPLATE="private-templates/functionality-testing/aos-${template_version}/ipi-on-osp/versioned-installer" \
		-w name=flexy-secrets,secret=flexy \
		-w name=install-dir,claimName=install-dir \
		-w name=plumbing-git,claimName=plumbing-git \
		--use-param-defaults --showlog