DAOS-14440 build: Update distro versions in GHA

The supported distro versions got missed in 56e3228 for the GitHub
Actions workflow.

Run-GHA: false
Skip-unit-tests: true
Skip-func-test-leap15: false
Skip-func-hw-test-medium: true
Skip-func-hw-test-medium-verbs-provider: true
Skip-func-hw-test-medium-ucx-provider: true
Test-tag: always_passes
Allow-unstable-test: true
Skip-PR-comments: true

Required-githooks: true

Signed-off-by: Brian J. Murrell <brian.murrell@intel.com>

.github/workflows/rpm-build-and-test.yml

@@ -5,10 +5,10 @@ env:
   #       build is done on the lowest version and test on the highest with a "sanity test"
   #       stage done on all versions in the list ecept the highest
   EL8_BUILD_VERSION: 8.6
-  EL8_VERSION: 8
+  EL8_VERSION: 8.8
   EL9_BUILD_VERSION: 9
   EL9_VERSION: 9
-  LEAP15_VERSION: 15.4
+  LEAP15_VERSION: 15.5
 
 on:
   workflow_dispatch: