build: allow a 'v' prefix when using the main-unstable tag

Signed-off-by: Niladri Halder <[email protected]>

nix/pkgs/images/default.nix

@@ -46,7 +46,7 @@ let
     # Script doesn't need to be used with main branch `--alias-tag <main-branch-style-tag>`.
     # The repo chart is already prepared.
     if [[ "$(semver validate ${tag})" == "valid" ]] &&
-      [[ ! ${tag} =~ ^([0-9]+\.[0-9]+\.[0-9]+-0-main-unstable(-[0-9]+){6}-0)$ ]]; then
+      [[ ! ${tag} =~ ^(v?[0-9]+\.[0-9]+\.[0-9]+-0-main-unstable(-[0-9]+){6}-0)$ ]]; then
       CHART_FILE=build/chart/Chart.yaml build/scripts/helm/publish-chart-yaml.sh --app-tag ${tag} --override-index ""
     fi
     chmod -w build/chart