Disable PostgreSQL 12 repo

infrastructure/cdn-in-a-box/traffic_ops/Dockerfile

@@ -39,13 +39,18 @@ RUN set -o nounset -o errexit && \
 	if [[ "${RHEL_VERSION%%.*}" -eq 7 ]]; then \
 		use_repo=''; \
 		enable_repo=''; \
+		disable_repo=''; \
 	else \
 		use_repo='--repo=pgdg13'; \
 		enable_repo='--enablerepo=powertools'; \
+		disable_repo='--disablerepo=pgdg12'; \
 	fi; \
 	dnf -y install "https://download.postgresql.org/pub/repos/yum/reporpms/EL-${RHEL_VERSION%%.*}-$(rpm --eval %_arch)/pgdg-redhat-repo-latest.noarch.rpm"; \
-	dnf -y install epel-release libicu; \
+	dnf -y $disable_repo install epel-release libicu; \
 	dnf -y $use_repo -- install postgresql13; \
+	if [[ -n "$disable_repo" ]]; then \
+		dnf -y remove pgdg-redhat-repo; \
+	fi; \
 	dnf -y $enable_repo install \
 		bind-utils           \
 		# find is required by to-access.sh