Skip EL8 PG19 when building/pushing all PostgreSQL versions

The EL8 guard in update_image and ci/push_images only fired when
POSTGRES_VERSION was explicitly set to 19. With an empty
POSTGRES_VERSION (the `all versions'' mode both scripts support) the
per-version loop still yielded 19 and attempted to build or push a
*-8-pg19 image that update_dockerfiles never generates.

Mirror the in-loop guard update_dockerfiles already uses. The existing
top-level check is kept so an explicit EL8+PG19 request still fails loudly.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 7211f17e-4ca6-41a8-9eb1-633c42a30149

Author: ihalatci-msft

ci/push_images

@@ -48,6 +48,10 @@ while read -r line; do
             if [ -n "${POSTGRES_VERSION}" ] && [ "${pgversion}" != "${POSTGRES_VERSION}" ] ; then
                 continue
             fi
+            if [[ "${release}" = '8' ]] && [[ "${pgversion}" = '19' ]]; then
+                # PGDG does not publish PostgreSQL 19 packages for EL8.
+                continue
+            fi
             if { [[ "${os}" = 'centos' ]] || [[ "${os}" = 'oraclelinux' ]]; } && \
                  [[ "${release}" = '6' ]] && [[ "${pgversion}" = '13' ]]; then
                 # CentOS and OracleLinux 6 doesn't have pg13 packages yet.

update_image

@@ -48,6 +48,10 @@ elif [[ "${os}" = 'centos' ]] || [[ "${os}" = 'oraclelinux' ]] || [[ "${os}" = '
         if [ -n "${POSTGRES_VERSION}" ] && [ "${pgversion}" != "${POSTGRES_VERSION}" ] ; then
             continue
         fi
+        if [[ "${release}" = '8' ]] && [[ "${pgversion}" = '19' ]]; then
+            # PGDG does not publish PostgreSQL 19 packages for EL8.
+            continue
+        fi
         if { [[ "${os}" = 'centos' ]] || [[ "${os}" = 'oraclelinux' ]]; } && \
              [[ "${release}" = '6' ]] && [[ "${pgversion}" = '13' ]]; then
             # CentOS and OracleLinux 6 doesn't have pg13 packages yet.