fix(cmd): remove unnecessary CMD in Dockerfile

The `CMD [ "/bin/bash/" ]` command in the last line of
`Dockerfile` is unnecessary. This can be changed with
`CMD [ "nvim" ]` for direct nvim start. However, with this setup it may
not be possible to exit and re-enter Neovim without quitting the
container.

Dockerfile

@@ -33,4 +33,3 @@ COPY . /root/.config/nvim
 RUN nvim --headless "+Lazy! install" +"MasonInstall ${LSP_LIST}" +qa
 RUN nvim --headless +"TSUpdateSync ${TS_LIST}" +qa
 
-CMD [ "/bin/bash" ]