feat(auto update): add script to update gitlab hosted packages

Signed-off-by: Aditya Alok <dev.aditya.alok@gmail.com>

scripts/updates/internal/termux_gitlab_auto_update.sh

@@ -0,0 +1,28 @@
+# shellcheck shell=bash
+# Default algorithm to use for packages hosted on hosts using gitlab-ci.
+termux_gitlab_auto_update() {
+	# Our local version of package.
+	local pkg_version
+	pkg_version="$(echo "${TERMUX_PKG_VERSION}" | cut -d: -f2-)"
+	local pkg_epoch
+	pkg_epoch="$(echo "${TERMUX_PKG_VERSION}" | cut -d: -f1)"
+
+	if [[ "${pkg_version}" == "${pkg_epoch}" ]]; then
+		# No epoch set.
+		pkg_epoch=""
+	else
+		pkg_epoch+=":"
+	fi
+
+	local latest_tag
+	latest_tag="$(
+		termux_gitlab_api_get_tag \
+			"${TERMUX_PKG_SRCURL}" "${TERMUX_PKG_UPDATE_TAG_TYPE}" "${TERMUX_GITLAB_API_HOST}"
+	)"
+	# No need to check for return code `2`, since gitlab api does not implement cache control.
+
+	if [[ -z "${latest_tag}" ]]; then
+		termux_error_exit "ERROR: Unable to get tag from ${TERMUX_PKG_SRCURL}"
+	fi
+	termux_pkg_upgrade_version "${pkg_epoch}${latest_tag}"
+}