pin docker image version, cleanups

.ci/docker-ci/arch/Dockerfile

@@ -1,4 +1,4 @@
-FROM archlinux:latest
+FROM archlinux:base-20220220.0.48372
 
 LABEL maintainer="mail@sobolevn.me"
 LABEL vendor="git-secret team"
@@ -9,8 +9,8 @@ RUN pacman -Syu --needed --noconfirm \
   gawk \
   git \
   gnupg \
-  diffutils \
   # Assumed to be present:
+  diffutils \
   file \
   make \
   procps

.github/workflows/test.yml

@@ -28,14 +28,14 @@ jobs:
     strategy:
       matrix:
         docker-env:
+          - alma
+          - alpine
+          - arch
           - debian-gnupg1  # We need to test legacy version of gnupg
           - debian-gnupg2
-          - ubuntu
-          - alpine
           - fedora
           - rocky
-          - alma
-          - arch
+          - ubuntu
     steps:
     - uses: actions/checkout@v2
     - name: Run checks