fix: update REQUIRED_VERSION_CONSTRAINT for Argo CD compatibility (#576)

Adjust the REQUIRED_VERSION_CONSTRAINT in the validate-values.yaml
to ensure compatibility with Argo CD versions, allowing for versions
up to but not including 3.1.

Author: ATGardner

charts/gitops-runtime/templates/hooks/pre-install/validate-values.yaml

@@ -31,7 +31,7 @@ spec:
         - name: ARGOCD_VERSION_PATH
           value: "/api/version"
         - name: REQUIRED_VERSION_CONSTRAINT
-          value: ">=2.12 <3"
+          value: ">=2.12 <3.1"
         - name: ARGOCD_ROOT_PATH
           value: {{ index .Values "global" "external-argo-cd" "server" "rootpath" | default "" }}
         command: ["sh", "-c"]