Fix: Install ca-certificates

Dockerfile

@@ -13,7 +13,7 @@ RUN echo "deb http://deb.debian.org/debian experimental main" >> /etc/apt/source
     echo "deb http://deb.debian.org/debian sid main" >> /etc/apt/sources.list && \
     apt-get update && \
     apt-get install -y --no-install-recommends -t experimental nodejs
-RUN apt-get update && apt-get install -y git dos2unix yarnpkg gnupg jq curl
+RUN apt-get update && apt-get install -y git dos2unix yarnpkg gnupg jq curl ca-certificates
 RUN git clone https://github.com/vector-im/element-web/ /src
 
 WORKDIR /src