Remove ubuntu 2004 from buildpackdeps workflow

Author: r0qs

.github/workflows/buildpack-deps.yml

@@ -25,7 +25,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        image_variant: [emscripten, ubuntu.clang.ossfuzz, ubuntu2004, ubuntu2404, ubuntu2404.clang]
+        image_variant: [emscripten, ubuntu.clang.ossfuzz, ubuntu2404, ubuntu2404.clang]
 
     steps:
       - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0