CI: Bump FreeBSD - add 15.0

Signed-off-by: Peter M <petermm@gmail.com>

Author: petermm

.github/workflows/build-and-test-on-freebsd.yaml

@@ -43,7 +43,7 @@ jobs:
       fail-fast: false
 
       matrix:
-        os_release: ["13.4", "14.2"]
+        os_release: ["13.5", "14.3", "15.0"]
 
     steps: