ci: Exercise creating dist tarball

Every release we have to cross our fingers that meson dist isn't
broken, and that's not fantastic. Let's test it on every pull
request, so we can catch PRs that break dist earlier.

.github/workflows/check.yml

@@ -119,6 +119,15 @@ jobs:
         XDG_DATA_DIRS: /usr/local/share:/usr/share
         ASAN_OPTIONS: detect_leaks=0 # Right now we're not fully clean, but this gets us use-after-free etc
 
+    - name: Create dist tarball
+      run: |
+        $RUN_CMD $AS_USER ls -la
+        $RUN_CMD $AS_USER timeout --signal=KILL -v ${TESTS_TIMEOUT}m meson dist -C ${BUILDDIR}
+      env:
+        TEST_IN_CI: 1
+        G_MESSAGES_DEBUG: all
+        ASAN_OPTIONS: detect_leaks=0 # Right now we're not fully clean, but this gets us use-after-free etc
+
     - name: Upload test logs
       uses: actions/upload-artifact@v3
       if: success() || failure()