chore: use gettext-envsubst alpine package instead of workaround

Dockerfile-alpine-slim.template

@@ -77,23 +77,8 @@ RUN set -x \
 # if we have leftovers from building, let's purge them (including extra, unnecessary build deps)
     && if [ -n "$tempDir" ]; then rm -rf "$tempDir"; fi \
     && if [ -f "/etc/apk/keys/abuild-key.rsa.pub" ]; then rm -f /etc/apk/keys/abuild-key.rsa.pub; fi \
-# Bring in gettext so we can get `envsubst`, then throw
-# the rest away. To do this, we need to install `gettext`
-# then move `envsubst` out of the way so `gettext` can
-# be deleted completely, then move `envsubst` back.
-    && apk add --no-cache --virtual .gettext gettext \
-    && mv /usr/bin/envsubst /tmp/ \
-    \
-    && runDeps="$( \
-        scanelf --needed --nobanner /tmp/envsubst \
-            | awk '{ gsub(/,/, "\nso:", $2); print "so:" $2 }' \
-            | sort -u \
-            | xargs -r apk info --installed \
-            | sort -u \
-    )" \
-    && apk add --no-cache $runDeps \
-    && apk del --no-network .gettext \
-    && mv /tmp/envsubst /usr/local/bin/ \
+# Add `envsubst` for templating environment variables
+    && apk add --no-cache gettext-envsubst \
 # Bring in tzdata so users could set the timezones through the environment
 # variables
     && apk add --no-cache tzdata \