tools: toolchain: update docker build command to include --no-cache
tools: toolchain: update docker build command to include --no-cache

If docker sees the Dockerfile hasn't changed it may reuse an old image, not
caring that context files and dependent images have in fact changed. This can
happen for us if install-dependencies.sh or the base Fedora image changed.

To make sure we always get a correct image, add --no-cache to the build command.
Message-Id: <03c6ee0b05c64bbabc7b7837666e56649ea1861c@scylladb.com>

avikivity/scylla,scylladb/scylla,avikivity/scylla,scylladb/scylla,scylladb/scylla,scylladb/scylla,avikivity/scylla