Remove support for python 3.8 (#17908)

### Pull Request Checklist

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* [X] Pull request is based on the develop branch
* [X] Pull request includes a [changelog
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The entry should:
- Be a short description of your change which makes sense to users.
"Fixed a bug that prevented receiving messages from other servers."
instead of "Moved X method from `EventStore` to `EventWorkerStore`.".
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* [X] [Code
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correct
(run the
[linters](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#run-the-linters))

---------

Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>

1 files changed, 2 insertions, 3 deletions

diff --git a/scripts-dev/build_debian_packages.py b/scripts-dev/build_debian_packages.py

index 88c8419400..6ee695b2ba 100755
--- a/scripts-dev/build_debian_packages.py
+++ b/scripts-dev/build_debian_packages.py
@@ -28,9 +28,8 @@ from typing import Collection, Optional, Sequence, Set
 # example)
 DISTS = (
     "debian:bullseye",  # (EOL ~2024-07) (our EOL forced by Python 3.9 is 2025-10-05)
-    "debian:bookworm",  # (EOL not specified yet) (our EOL forced by Python 3.11 is 2027-10-24)
-    "debian:sid",  # (EOL not specified yet) (our EOL forced by Python 3.11 is 2027-10-24)
-    "ubuntu:focal",  # 20.04 LTS (EOL 2025-04) (our EOL forced by Python 3.8 is 2024-10-14)
+    "debian:bookworm",  # (EOL 2026-06) (our EOL forced by Python 3.11 is 2027-10-24)
+    "debian:sid",  # (rolling distro, no EOL)
     "ubuntu:jammy",  # 22.04 LTS (EOL 2027-04) (our EOL forced by Python 3.10 is 2026-10-04)
     "ubuntu:noble",  # 24.04 LTS (EOL 2029-06)
     "ubuntu:oracular",  # 24.10 (EOL 2025-07)