Merge pull request #302 from saito-hideki/issue/301

[CI] Fix exit code in CI entrypoint to address shellckeck issue

SUMMARY
Fix wrong exit code -1 in CI entrypoint to address shellcheck failure:

Fixes #301

ISSUE TYPE

CI tests Pull Request

COMPONENT NAME

tests/utils/shippable/shippable.sh

ADDITIONAL INFORMATION
None

Reviewed-by: None <None>

changelogs/fragments/302_shippable_exit_code.yml

@@ -0,0 +1,3 @@
+---
+trivial:
+- CI tests - fix exit code to address shellckeck test issue (https://github.com/ansible-collections/ansible.posix/issues/301).

tests/utils/shippable/shippable.sh

@@ -50,7 +50,7 @@ function retry
         echo "@* -> ${result}"
     done
     echo "Command '@*' failed 3 times!"
-    exit -1
+    exit 255
 }
 
 command -v pip