Also run Foolscap-only integration tests.

.github/workflows/ci.yml

@@ -164,18 +164,20 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        include:
-          - os: macos-12
-            python-version: "3.11"
-            force-foolscap: false
-          - os: windows-latest
-            python-version: "3.11"
-            force-foolscap: false
+        os:
           # 22.04 has some issue with Tor at the moment:
           # https://tahoe-lafs.org/trac/tahoe-lafs/ticket/3943
+          - ubuntu-20.04
+          - macos-12
+          - windows-latest
+        python-version:
+          - "3.11"
+        force-foolscap:
+          - false
+        include:
           - os: ubuntu-20.04
             python-version: "3.10"
-            force-foolscap: false
+            force-foolscap: true
     steps:
 
       - name: Install Tor [Ubuntu]