ci: WSA build fix typo (#370)

.github/workflows/build-kernel-wsa.yml

@@ -8,6 +8,7 @@ on:
   pull_request:
     branches: ["main"]
     paths:
+      - ".github/workflows/build-kernel-wsa.yml"
       - "kernel/**"
   workflow_call:
   workflow_dispatch:
@@ -141,7 +142,7 @@ jobs:
           export TITLE
           export VERSION="${{ env.kernelsu_version }}"
           echo "[+] Compress images"
-          $GZIP -n -f -9 "${{ env.file_path }}"
+          gzip -n -f -9 "${{ env.file_path }}"
           echo "[+] Image to upload"
           find . -type f -name "*.gz"
           if [ -n "${{ secrets.BOT_TOKEN }}" ]; then