[master] 1a6bef962 [cci] update the machine executor version

[Guillaume Quintard]

commit 1a6bef9622c78d4adc0c7a59e9794b389c46a8cc
Author: Guillaume Quintard <guillaume at varnish-software.com>
Date:   Tue Nov 3 16:11:12 2020 -0800

    [cci] update the machine executor version
    
    Long story short: newer coreutils use `statx` which isn't supported by
    old kernel, so the `debian:bullseye` images blew up.

diff --git a/.circleci/config.yml b/.circleci/config.yml
index 7b600094a..ea34dc7ab 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -97,7 +97,7 @@ jobs:
         description: the base Docker image for Dockerfile
         type: string
     machine:
-      image: ubuntu-1604:201903-01
+      image: ubuntu-2004:202010-01
     steps:
       - attach_workspace:
           at: ~/project