Add no version or version not found check for install

install.sh

@@ -4,6 +4,15 @@ BASE_FOLDER=$(dirname "$(readlink -f "$0")")"/";
 # shellcheck source=init.sh
 . "${BASE_FOLDER}init.sh";
 
+if [ -z "${1}" ]; then
+    echo "Please give a Gitea version to upgrade to";
+    exit;
+fi;
+if [ ! -f "${download_folder}gitea-${1}-${arch}" ]; then
+    echo "Cannot find file: ${download_folder}gitea-${1}-${arch}";
+	exit;
+fi;
+
 echo -e "Update gitea to ${1} ... ";
 systemctl stop gitea;
 cp "${download_folder}gitea-${1}-${arch}" "${target_file}";