Fix typo in GA

Author: phracek

.github/workflows/container-tests.yml

@@ -58,7 +58,7 @@ jobs:
               context="RHEL8"
               tmt_plan="rhel8-docker"
             else
-              if [ '${{ matrix.os }} == "rhel9" ]; then
+              if [ "${{ matrix.os }}" == "rhel9" ]; then
                 compose="RHEL-9.4.0-Nightly"
                 context="RHEL9"
                 tmt_plan="rhel9-docker"