Add release selection for the GitHub-released server types (#4339)

scripts/start-deployNanoLimbo

@@ -4,12 +4,21 @@
 . "$(dirname "$0")/start-utils"
 isDebugging && set -x
 
-if ! SERVER=$(mc-image-helper github download-latest-asset \
+: "${NANOLIMBO_RELEASE:=latest}"
+
+# Only pass --release-tag when a specific release was requested; helper treats
+# omitted as latest
+nanolimboReleaseArgs=()
+[[ ${NANOLIMBO_RELEASE} == latest ]] || nanolimboReleaseArgs+=(--release-tag="${NANOLIMBO_RELEASE}")
+
+if ! SERVER=$(mc-image-helper github download-asset \
+  "${nanolimboReleaseArgs[@]}" \
   --output-directory=/data \
   --name-pattern="NanoLimbo(-.+?(?<!-sources))?\.jar" \
   BoomEaro/NanoLimbo
   ); then
-    logError "Failed to download NanoLimbo"
+    logError "Failed to download NanoLimbo release ${NANOLIMBO_RELEASE}"
+    logError "Ensure NANOLIMBO_RELEASE is one of the releases at https://github.com/BoomEaro/NanoLimbo/releases"
     exit 1
 fi