fix: add :Z to volume mount (#1149)
fix: add :Z to volume mount (#1149)

On SELinux-enabled systems, if the `\$PWD` has any security contexts, mounting
the filesystem can result in permission denied errors. The solution is to
append `:Z` which will have the mounted filesystem share the security contexts.
googleapis/google-cloud-cpp-spanner,googleapis/google-cloud-cpp-spanner,googleapis/google-cloud-cpp-spanner,googleapis/google-cloud-cpp-spanner