ci: add Debian Bullseye i386 and GCC sanitizers

Add i386 and GCC sanitizer builds on Debian Bullseye.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

.github/workflows/ci.yml

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 677c415..57a58e2 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -98,6 +98,20 @@
             mode: no-maintainer
             variant: i386
 
+          - container: "debian:bullseye"
+            arch: i386
+            compiler: gcc -m32
+            cross_compile: i686-linux-gnu
+            mode: maintainer
+            variant: i386
+
+          - container: "debian:bullseye"
+            arch: i386
+            compiler: gcc -m32
+            cross_compile: i686-linux-gnu
+            mode: no-maintainer
+            variant: i386
+
           - container: "debian:buster"
             arch: i386
             compiler: gcc -m32
@@ -188,6 +202,12 @@
             mode: maintainer
             variant: sanitizers
 
+          - container: "debian:bullseye"
+            arch: x86-64
+            compiler: gcc
+            mode: maintainer
+            variant: sanitizers
+
           - container: "debian:buster"
             arch: x86-64
             compiler: gcc