Fix olddeps build (#15626)

Do an `apt update` before install packages.

Author: clokep

.github/workflows/tests.yml

@@ -314,8 +314,9 @@ jobs:
       # There aren't wheels for some of the older deps, so we need to install
       # their build dependencies
       - run: |
+          sudo apt update
           sudo apt-get -qq install build-essential libffi-dev python-dev \
-          libxml2-dev libxslt-dev xmlsec1 zlib1g-dev libjpeg-dev libwebp-dev
+            libxml2-dev libxslt-dev xmlsec1 zlib1g-dev libjpeg-dev libwebp-dev
 
       - uses: actions/setup-python@v4
         with:

changelog.d/15626.misc

@@ -0,0 +1 @@
+Fix the olddeps CI.