Stop using deprecated Ubuntu 20.04 in CI

actions/runner-images#11101

.github/workflows/ci.yml

@@ -58,11 +58,6 @@ jobs:
             os: ubuntu-latest
             experimental: false
             nox-session: test_integration
-          # OpenSSL 1.1.1
-          - python-version: "3.9"
-            os: ubuntu-20.04
-            experimental: false
-            nox-session: test-3.9
           # pypy
           - python-version: "pypy-3.10"
             os: ubuntu-latest
@@ -73,11 +68,6 @@ jobs:
             os: ubuntu-latest
             experimental: false
             nox-session: test_brotlipy
-          # Test CPython with a broken hostname_checks_common_name (the fix is in 3.9.3)
-          - python-version: "3.9.2"
-            os: ubuntu-20.04  # CPython 3.9.2 is not available for ubuntu-22.04.
-            experimental: false
-            nox-session: test-3.9
           - python-version: "3.12"
             os: ubuntu-latest
             nox-session: emscripten(node)
@@ -94,7 +84,7 @@ jobs:
             experimental: true
 
     runs-on: ${{ matrix.os }}
-    name: ${{ fromJson('{"macos-15":"macOS","windows-latest":"Windows","ubuntu-latest":"Ubuntu","ubuntu-20.04":"Ubuntu 20.04 (OpenSSL 1.1.1)"}')[matrix.os] }} ${{ matrix.python-version }} ${{ matrix.nox-session}}
+    name: ${{ fromJson('{"macos-15":"macOS","windows-latest":"Windows","ubuntu-latest":"Ubuntu"}')[matrix.os] }} ${{ matrix.python-version }} ${{ matrix.nox-session}}
     continue-on-error: ${{ matrix.experimental }}
     timeout-minutes: 10
     steps:

.github/workflows/lint.yml

@@ -7,7 +7,7 @@ permissions:
 
 jobs:
   lint:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     timeout-minutes: 10
 
     steps: