bugfix: "Deploy natives snapshot" step always detects native changes

.github/workflows/main.yml

@@ -232,7 +232,7 @@ jobs:
               else
                 # We check if the native code changed.
                 echo "Detect changes"
-                if [ "$NATIVE_CHANGES" = "" ];then NATIVE_CHANGES="$(git diff-tree --name-only "$GITHUB_SHA" "$nativeSnapshot"  --  jme3-android-native/)"; fi
+                NATIVE_CHANGES="$(git diff-tree --name-only "$GITHUB_SHA" "$nativeSnapshot"  --  jme3-android-native/)"; fi
               fi
             fi