Attempt to fix the workflow

Author: thresheek

.github/workflows/nginx-buildbot.yml

@@ -45,7 +45,7 @@ jobs:
     strategy:
       matrix:
         #        os: [ alpine-3.19, amazonlinux-2, amazonlinux-2023, debian-11, debian-12, freebsd-14, rhel-8, rhel-9, sles-12, ubuntu-20.04, ubuntu-22.04, ubuntu-24.04 ]
-        os: [ ubuntu-22.04 ]
+        os: [ ubuntu-22.04, freebsd-14, sles-12 ]
         arch: [ amd64, arm64 ]
         subarch: [ '' ]
         asan: [ '' ]