fix: incorporate PR feedback

Author: cadojo

src/julia/devcontainer-feature.json

@@ -17,7 +17,11 @@
         "additionalChannels": {
             "type": "string",
             "default": "",
-            "description": "Additional Juliaup channels to install, separated by commas (e.g., 'nightly,1.10')"
+            "description": "Additional Juliaup channels to install, separated by commas (e.g., 'nightly,1.10')",
+			"proposals": [
+                "",
+ 				"lts,nightly",
+ 			]
         }
     },
     "installsAfter": [

src/julia/install.sh

@@ -59,7 +59,7 @@ export DEBIAN_FRONTEND=noninteractive
 cleanup_apt
 check_packages curl ca-certificates
 
-su ${USERNAME} -c "curl -fsSL https://install.julialang.org | sh -s -- --yes --default-channel ${CHANNEL}"
+su "${USERNAME}" -c "curl -fsSL https://install.julialang.org | sh -s -- --yes --default-channel ${CHANNEL}"
 
 for channel in "${channels[@]}"; do
     # if channel is not empty and not equal to the default channel...

test/julia/scenarios.json

@@ -48,4 +48,4 @@
 			}
 		}
 	}
-}
+}