8331730: [8u] GHA: update sysroot for cross builds to Debian bullseye

Reviewed-by: serb

Author: zzambers

.github/workflows/submit.yml

@@ -401,7 +401,7 @@ jobs:
           --verbose
           --include=fakeroot,symlinks,build-essential,libx11-dev,libxext-dev,libxrender-dev,libxrandr-dev,libxtst-dev,libxt-dev,libcups2-dev,libfontconfig1-dev,libasound2-dev,libfreetype6-dev,libpng-dev,libffi-dev
           --resolve-deps
-          buster
+          bullseye
           ~/sysroot-${{ matrix.debian-arch }}
           http://httpredir.debian.org/debian/
         if: matrix.debian-arch != '' && steps.cache-sysroot.outputs.cache-hit != 'true'