ci: MariaDB - add back 11.4 and add 11.5 (#3266)

* Revert "fix(ci): disable `mariadb_verylatest` pass for RusTLS"

This reverts commit c78425b.

MariaDB 11.4.2 now includes the upstream fix for this.

Closes: 3091

* ci: mariadb 11.4 now GA/Stable

.github/workflows/sqlx.yml

@@ -367,13 +367,9 @@ jobs:
     runs-on: ubuntu-22.04
     strategy:
       matrix:
-        mariadb: [verylatest, 10_11, 10_4]
+        mariadb: [verylatest, 11_4, 10_11, 10_4]
         runtime: [async-std, tokio]
         tls: [native-tls, rustls, none]
-        exclude:
-          # FIXME: `rustls` cannot accept MariaDB's new self-signed certificates: https://github.com/launchbadge/sqlx/issues/3091
-          - mariadb: verylatest
-            tls: rustls
     needs: check
     steps:
       - uses: actions/checkout@v2