ci: Bump Ubuntu to 18.04 LTS.

Ubuntu 16.04 LTS went EOL at the end of April 2021.

Author: QuLogic

.github/workflows/tests.yml

@@ -22,18 +22,18 @@ jobs:
       matrix:
         include:
           - name-suffix: "(Minimum Versions)"
-            os: ubuntu-16.04
+            os: ubuntu-18.04
             python-version: 3.7
             extra-requirements: '-c requirements/testing/minver.txt'
             pyqt5-ver: '==5.8 sip==4.19.7'  # oldest versions with a Py3.7 wheel.
             delete-font-cache: true
             XVFB_RUN: xvfb-run -a
-          - os: ubuntu-16.04
+          - os: ubuntu-18.04
             python-version: 3.7
             extra-requirements: '-r requirements/testing/extra.txt'
             XVFB_RUN: xvfb-run -a
             CFLAGS: "-fno-lto"  # Ensure that disabling LTO works.
-          - os: ubuntu-16.04
+          - os: ubuntu-18.04
             python-version: 3.8
             extra-requirements: '-r requirements/testing/extra.txt'
             XVFB_RUN: xvfb-run -a
@@ -156,12 +156,8 @@ jobs:
           # libraries cannot be loaded at runtime, so an actual import is a
           # better check).
           if [[ "${{ runner.os }}" != 'macOS' ]]; then
-            # PyGObject, pycairo, and cariocffi do not install on OSX 10.12;
-            # pycairo 1.20+ requires a new version of Cairo, unavailable on
-            # Ubuntu 16.04, so PyGObject must be installed without build
-            # isolation in order to pick up the lower pre-installed version.
-             python -m pip install --upgrade 'pycairo<1.20.0' 'cairocffi>=0.8' &&
-             python -m pip install --upgrade --no-build-isolation PyGObject &&
+            # PyGObject, pycairo, and cariocffi do not install on OSX 10.12.
+             python -m pip install --upgrade pycairo 'cairocffi>=0.8' PyGObject &&
                python -c 'import gi; gi.require_version("Gtk", "3.0"); from gi.repository import Gtk' &&
                echo 'PyGObject is available' ||
                echo 'PyGObject is not available'
@@ -180,7 +176,7 @@ jobs:
                echo 'PySide2 is not available'
           fi
           python -m pip install --upgrade \
-            -f https://extras.wxpython.org/wxPython4/extras/linux/gtk3/ubuntu-16.04 \
+            -f https://extras.wxpython.org/wxPython4/extras/linux/gtk3/ubuntu-18.04 \
             wxPython &&
             python -c 'import wx' &&
             echo 'wxPython is available' ||

azure-pipelines.yml

@@ -6,13 +6,13 @@
 strategy:
   matrix:
     Linux_py37:
-      vmImage: 'ubuntu-16.04'
+      vmImage: 'ubuntu-18.04'
       python.version: '3.7'
     Linux_py38:
-      vmImage: 'ubuntu-16.04'
+      vmImage: 'ubuntu-18.04'
       python.version: '3.8'
     Linux_py39:
-      vmImage: 'ubuntu-16.04'
+      vmImage: 'ubuntu-18.04'
       python.version: '3.9'
     macOS_py37:
       vmImage: 'macOS-10.15'