issue2551284 - python 3.12b4 breaks email address parsing

I disabled testing under 3.12 because it as breaking the build.
Apparently the experimental setting wasn't working right. Try tweaking
syntax to see if I can get a full run with a broken 3.12 and still
pass testing.

Author: rouilj

.github/workflows/ci-test.yml

@@ -34,7 +34,7 @@ jobs:
 
     # run the finalizer for coveralls even if one or more
     # experimental matrix runs fail.
-    # continue-on-error: ${{ matrix.experimental }}
+    continue-on-error: ${{ matrix.experimental }}
 
     #runs-on: ubuntu-latest
     # use below if running on multiple OS's.
@@ -65,9 +65,9 @@ jobs:
 
         include:
             # example: if 3.12 fails the jobs still succeeds
-            #- python-version: 3.12
-            #  os: ubuntu-22.04
-            #  experimental: [true]
+            - python-version: 3.12
+              os: ubuntu-22.04
+              experimental: true
 
             # 3.6 not available on new 22.04 runners, so run on 20.04 ubuntu
             - python-version: 3.6