pipeline isn’t picking up the 18 line because your regex for the full field only allows digits and dots ([0-9.]+), so it skips the "full": "18beta1" entry.

.github/workflows/build_and_test.yml

@@ -36,7 +36,7 @@ jobs:
       pg15_version: '{ "major": "15", "full": "15.12" }'
       pg16_version: '{ "major": "16", "full": "16.8" }'
       pg17_version: '{ "major": "17", "full": "17.4" }'
-      pg18_version: '{ "major": "17", "full": "18beta1" }'
+      pg18_version: '{ "major": "18", "full": "18beta1" }'
       upgrade_pg_versions: "15.12-16.8-17.4-18beta1"
     steps:
       # Since GHA jobs need at least one step we use a noop step here.

.github/workflows/packaging-test-pipelines.yml

@@ -29,7 +29,7 @@ jobs:
           # Postgres versions are stored in .github/workflows/build_and_test.yml
           # file in json strings with major and full keys.
           # Below command extracts the versions and get the unique values.
-          pg_versions=$(cat .github/workflows/build_and_test.yml | grep -oE '"major": "[0-9]+", "full": "[0-9.]+"' | sed -E 's/"major": "([0-9]+)", "full": "([0-9.]+)"/\1/g' | sort | uniq | tr '\n', ',')
+          pg_versions=$(cat .github/workflows/build_and_test.yml | grep -oE '"major": "[0-9]+", "full": "[^"]+"' | sed -E 's/.*"major": "([0-9]+)".*/\1/' | sort -n | uniq | tr '\n' ',')
           pg_versions_array="[ ${pg_versions} ]"
           echo "Supported PG Versions: ${pg_versions_array}"
           # Below line is needed to set the output variable to be used in the next job