[tests] Use ubuntu 20.04 for Python 3.6 tests

Python 3.6 has reached EOL 1 year ago and is no longer supported by
ubuntu-latest. Therefore use 20.04 instead.

Bug: T325468
Change-Id: I3cfc60e74c657289026955e2f5111b426795250a
---
M .github/workflows/oauth_tests-ci.yml
M .github/workflows/pywikibot-ci.yml
M .github/workflows/login_tests-ci.yml
3 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/login_tests-ci.yml b/.github/workflows/login_tests-ci.yml
index 01656a1..6f10554 100644
--- a/.github/workflows/login_tests-ci.yml
+++ b/.github/workflows/login_tests-ci.yml
@@ -26,14 +26,17 @@
         python-version: ["pypy3.7", "3.7", "3.8", "3.9", "3.10", "3.11", "3.12.0-alpha - 3.12.0"]
         site: ['wikipedia:en', 'wikisource:zh']
         include:
+          # ubuntu-20.04 required for Python 3.6
           - python-version: 3.6
             site: False
             family: wpbeta
             code: en
+            os: ubuntu-20.04
           - python-version: 3.6
             site: False
             family: wpbeta
             code: zh
+            os: ubuntu-20.04
           - python-version: 3.8
             site: wsbeta:en
           - python-version: 3.7
@@ -44,6 +47,7 @@
             site: wiktionary:ar
           - python-version: 3.6
             site: wikidata:wikidata
+            os: ubuntu-20.04
           - python-version: 3.8
             site: wowwiki:uk
           - python-version: "3.12.0-alpha - 3.12.0"
@@ -51,7 +55,6 @@
           - python-version: 3
             site: wikipedia:de
             os: macOS-latest
-          # ubuntu-20.04 required for Python 3.6
           - python-version: 3.6
             site: wikipedia:en
             os: ubuntu-20.04
diff --git a/.github/workflows/oauth_tests-ci.yml b/.github/workflows/oauth_tests-ci.yml
index 704ff9e..93dee04 100644
--- a/.github/workflows/oauth_tests-ci.yml
+++ b/.github/workflows/oauth_tests-ci.yml
@@ -29,6 +29,7 @@
         code: ['test']
         domain:  ['test.wikipedia.org']
         include:
+          # ubuntu-20.04 required for Python 3.6
           - python-version: 3.6
             family: wpbeta
             code: en
@@ -38,7 +39,6 @@
             family: wpbeta
             code: zh
             domain: zh.wikipedia.beta.wmflabs.org
-          # ubuntu-20.04 required for Python 3.6
           - python-version: 3.6
             family: wikipedia
             code: test
diff --git a/.github/workflows/pywikibot-ci.yml b/.github/workflows/pywikibot-ci.yml
index 8fb7e0c..083e083 100644
--- a/.github/workflows/pywikibot-ci.yml
+++ b/.github/workflows/pywikibot-ci.yml
@@ -30,6 +30,7 @@
         site: ['wikipedia:en', 'wikisource:zh']
         test_prod_only: [true]
         include:
+          # ubuntu-20.04 required for Python 3.6
           - python-version: 3.6
             site: False
             family: wpbeta
@@ -62,7 +63,6 @@
           - python-version: 3
             site: wikipedia:de
             os: macOS-latest
-          # ubuntu-20.04 required for Python 3.6
           - python-version: 3.6
             site: wikipedia:en
             test_prod_only: true

