fixed empty param value

Former-commit-id: adf46c51640d532869cff8afb2c29ecdde5b72ac

cli/dockerfile

@@ -9,5 +9,5 @@ RUN set -x \
     
 WORKDIR /usr/src/app/SingleFile/cli
 
-ENTRYPOINT ["./single-file", "--browser-executable-path", "/usr/bin/chromium-browser", "--filename-template", "", "--browser-args", "[\"--no-sandbox\"]"]
+ENTRYPOINT ["./single-file", "--browser-executable-path", "/usr/bin/chromium-browser", "--filename-template=''", "--browser-args", "[\"--no-sandbox\"]"]
 CMD ["https://github.com/Zenika/alpine-chrome"]