[libxml2] Update MAINTAINERS.md

[Nick Wellnhofer <nwellnhof src gnome org>]

commit 4eca70e584ffc696be54a05ae9ded57162be587f
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Fri Aug 26 14:50:21 2022 +0200

    Update MAINTAINERS.md

 MAINTAINERS.md | 47 +++++++++++++++++++++++++++++++++++++----------
 1 file changed, 37 insertions(+), 10 deletions(-)
---
diff --git a/MAINTAINERS.md b/MAINTAINERS.md
index 7d46c5b9..89d00fb3 100644
--- a/MAINTAINERS.md
+++ b/MAINTAINERS.md
@@ -1,24 +1,26 @@
-# Making a release
+# Maintainer's Guide
 
-## Rebuild generated files and documentation
+## Making a release
+
+### Rebuild generated files and documentation
 
 The documentation and some generated files can be rebuilt by running
 
     make -C doc rebuild
 
-This requires `xsltproc` to be installed.
+This requires `xsltproc` and the libxml2 Python bindings to be installed.
 
-## Update the NEWS file
+### Update the NEWS file
 
 You can get started by running
 
     git log --format='- %s (%an)' [previous-release-tag]..
 
-## Bump the version number
+### Bump the version number
 
 Edit the version number in `configure.ac` if you haven't done so already.
 
-## Build the tarball
+### Build the tarball
 
 I'd recommend to build the tarball by running
 
@@ -26,7 +28,7 @@ I'd recommend to build the tarball by running
 
 which performs some useful checks as well.
 
-## Upload the tarball
+### Upload the tarball
 
 Follow the instructions at
 <https://wiki.gnome.org/MaintainersCorner/Releasing>:
@@ -34,20 +36,45 @@ Follow the instructions at
     scp libxml2-[version].tar.xz master.gnome.org:
     ssh master.gnome.org ftpadmin install libxml2-[version].tar.xz
 
-## Tag the release
+### Tag the release
 
 Create an annotated tag and push it:
 
     git tag -a [version] -m 'Release [version]'
     git push origin [version]
 
-## Create a GitLab release
+### Create a GitLab release
 
 Create a new GitLab release on
 <https://gitlab.gnome.org/GNOME/libxml2/-/releases>.
 
-## Announce the release
+### Announce the release
 
 Announce the release by sending an email to the mailing list at
 xml gnome org.
 
+## Updating the CI Docker image
+
+Note that the CI image is used for libxslt as well. Run the following
+commands with the Dockerfile passed as heredoc:
+
+    docker login registry.gitlab.gnome.org
+
+    docker build -t registry.gitlab.gnome.org/gnome/libxml2 - <<'EOF'
+    FROM ubuntu:22.04
+    ENV DEBIAN_FRONTEND=noninteractive
+    RUN apt-get update && \
+       apt-get upgrade -y && \
+       apt-get install -y --no-install-recommends \
+           curl git ca-certificates \
+           autoconf automake libtool pkg-config \
+           make gcc clang llvm \
+           zlib1g-dev liblzma-dev libgcrypt-dev \
+           python2-dev python3-dev \
+           cmake
+    WORKDIR /tests
+    RUN curl https://www.w3.org/XML/Test/xmlts20080827.tar.gz |tar xz
+    EOF
+
+    docker push registry.gitlab.gnome.org/gnome/libxml2
+