[gbm-web] flat-manager: Update to Ubuntu 20.04

[Bartłomiej Piotrowski <bpiotrowski src gnome org>]

commit f133467bb782b8c2951479fad068db0026482f5c
Author: Bartłomiej Piotrowski <bpiotrowski gnome org>
Date:   Fri Apr 30 14:41:30 2021 +0200

    flat-manager: Update to Ubuntu 20.04

 flat-manager/Dockerfile                   | 4 ++--
 flat-manager/ppa_alexlarsson_flatpak.list | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/flat-manager/Dockerfile b/flat-manager/Dockerfile
index 031e215..5608249 100644
--- a/flat-manager/Dockerfile
+++ b/flat-manager/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:18.04 as builder
+FROM ubuntu:20.04 as builder
 
 RUN apt-get update && apt-get install -y git libpq-dev curl build-essential libgpgme-dev
 RUN curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs > rustup.sh && \
@@ -15,7 +15,7 @@ RUN cd flat-manager-ostree && /root/.cargo/bin/cargo build --release
 ADD gpg-heartbeat.c /gpg-heartbeat.c
 RUN gcc -s /gpg-heartbeat.c $(gpgme-config --libs --cflags) -o /gpg-heartbeat
 
-FROM ubuntu:18.04
+FROM ubuntu:20.04
 
 RUN apt-get update && apt-get install -y gnupg2
 ADD ppa_alexlarsson_flatpak.list /etc/apt/sources.list.d/
diff --git a/flat-manager/ppa_alexlarsson_flatpak.list b/flat-manager/ppa_alexlarsson_flatpak.list
index d10254b..7b51c98 100644
--- a/flat-manager/ppa_alexlarsson_flatpak.list
+++ b/flat-manager/ppa_alexlarsson_flatpak.list
@@ -1 +1 @@
-deb http://ppa.launchpad.net/alexlarsson/flatpak/ubuntu bionic main
+deb http://ppa.launchpad.net/alexlarsson/flatpak/ubuntu focal main