Add OpenSSL to docker image (#10741)

Summary:
Update the docker image with OpenSSL, required by the folly build.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10741

Reviewed By: jay-zhuang

Differential Revision: D39831081

Pulled By: anand1976

fbshipit-source-id: 900154f70a456d1b6f9e384b8bdbcc227af4adbc

build_tools/ubuntu20_image/Dockerfile

@@ -16,6 +16,7 @@ RUN apt-get install -y libgflags-dev libtbb-dev
 RUN apt-get install -y libsnappy-dev zlib1g-dev libbz2-dev liblz4-dev libzstd-dev
 # install cmake
 RUN apt-get install -y cmake
+RUN apt-get install -y libssl-dev
 # install clang-13
 WORKDIR /root
 RUN wget https://apt.llvm.org/llvm.sh