👷(ci) lint helmfile

Introduced by @rouja. Added a new linter to ensure helm and yaml
files can be properly parsed into templates.
ArgoCD can not break anymore.

bin/validate-helm-configuration.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+set -e
+
+HELMFILE=src/helm/helmfile.yaml
+
+environments=$(awk '/environments:/ {flag=1; next} flag && NF {print} !NF {flag=0}' "$HELMFILE" | grep -E '^[[:space:]]{2}[a-zA-Z]+' | sed 's/^[[:space:]]*//;s/:.*//')
+
+for env in $environments; do
+	echo "################### $env lint ###################"
+	helmfile -e $env -f src/helm/helmfile.yaml lint || exit 1
+	echo -e "\n"
+done