chore: change spec for 3.13.

I have it set up so I can just use 3.13 as the version and it will pull
alphas. no need for -alpha in spec.

[skip travis]

Author: rouilj

.github/workflows/ci-test.yml

@@ -68,8 +68,10 @@ jobs:
         experimental: [ false ]
 
         include:
-            # example: if 3.12 fails the jobs still succeeds
-            - python-version: 3.13-alpha
+            # example: if 3.13 fails the jobs still succeeds
+            # allow-prereleases in setup-python allows alpha/beta
+            # releases to run
+            - python-version: 3.13
               os: ubuntu-22.04
               experimental: true