github CI: remove tags from container names

Best to be latest.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

.github/workflows/nightly_Linux_distributions.yml

@@ -19,8 +19,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        # arch suffering this issue: https://github.com/abseil/abseil-cpp/issues/709
-        container_image: ["fedora:latest", "debian:11", "archlinux:base", "ubuntu:22.04", "tgagor/centos:stream9", "alpine:3.17"]
+        container_image: ["fedora", "debian", "archlinux", "ubuntu", "tgagor/centos", "alpine"]
         compiler: [g++, clang++]
         build_type: [Release, Debug]
         shared_libraries: [ON, OFF]