feat: Add gettext-base for envsubst (#19)

* Add gettext-base (opendefensecloud/solution-arsenal#266)
* One package per line (better diffs)

Author: dermorz

Dockerfile

@@ -2,6 +2,8 @@ FROM ghcr.io/falcondev-oss/actions-runner:2.332.0
 USER root
 RUN apt-get update -qy \
     && apt-get install -y --no-install-recommends --fix-missing \
-    build-essential shellcheck \
+    build-essential \
+    gettext-base \
+    shellcheck \
     && rm -rf /var/lib/apt/lists/*
 USER runner