Install libc++ package on CI images of Ubuntu 22.04 (#402)

Author: egorzhdan

swift-ci/master/ubuntu/22.04/Dockerfile

@@ -11,6 +11,7 @@ RUN apt-get -y update && apt-get -y install \
   file                  \
   git                   \
   icu-devtools          \
+  libc++-15-dev         \
   libcurl4-openssl-dev  \
   libedit-dev           \
   libicu-dev            \