ci: Move Qt 5.13 back to Travis

We get another seccomp-bpf failure there

.github/workflows/ci.yml

@@ -83,9 +83,10 @@ jobs:
             os: ubuntu-20.04
             python: 3.8
           ### PyQt 5.13 (Python 3.8)
-          - testenv: py38-pyqt513
-            os: ubuntu-20.04
-            python: 3.8
+          # FIXME: seccomp-bpf failure in syscall 0230
+          # - testenv: py38-pyqt513
+          #   os: ubuntu-20.04
+          #   python: 3.8
           ### PyQt 5.14 (Python 3.8)
           - testenv: py38-pyqt514
             os: ubuntu-20.04

.travis.yml

@@ -16,6 +16,13 @@ matrix:
     - python: 3.7
       env: TESTENV=py37-pyqt511
 
+    ### PyQt 5.13 (Python 3.8)
+    - env: TESTENV=py38-pyqt513
+      addons:
+        apt:
+          packages:
+          - libxkbcommon-x11-0
+
     ### PyQt 5.15 (Python 3.8, with coverage)
     - env: TESTENV=py38-pyqt515-cov
       addons: