Add Fedora 32, drop Fedora 31

Also drop other (unused) Linux distributions.

.gitlab-ci.yml

@@ -204,11 +204,11 @@ centos:8:amd64:packer:
         - packer/centos/*
       when: always
 
-fedora:31:amd64:docker:
+fedora:32:amd64:docker:
   stage: images
   variables:
     DISTROS: fedora
-    VERSIONS: 31
+    VERSIONS: 32
     ARCHS: amd64
   <<: *linux_amd64
   <<: *docker_image_job

docker/Makefile

 DISTROS ?= alpine centos debian fedora tumbleweed ubuntu
 ARCHS ?= amd64 i386
 
-default_alpine_VERSIONS := 3.10 3.11
+default_alpine_VERSIONS := 3.11
 default_centos_VERSIONS := centos6 centos7 centos8
-default_debian_VERSIONS := stretch buster bullseye sid
-default_fedora_VERSIONS := 30 31
+default_debian_VERSIONS := stretch buster sid
+default_fedora_VERSIONS := 32
 default_tumbleweed_VERSIONS := latest
 default_ubuntu_VERSIONS := xenial bionic
 ifneq (,$(VERSIONS))