Add missing lifted-base package dependency

Keter fails to install when missing lifted-base package dependency.

```bash
$ cabal-dev install keter
```
got ExitFailure 1.
it outputs:

```
...
Configuring classy-prelude-0.5.0...
Building classy-prelude-0.5.0...
Preprocessing library classy-prelude-0.5.0...

ClassyPrelude.hs:122:8:
    Could not find module `Data.IORef.Lifted'
    Use -v to see a list of the files searched for.
...
cabal: Error: some packages failed to install:
classy-prelude-0.5.0 failed during the building phase. The exception was:
ExitFailure 1
http-reverse-proxy-0.2.0 depends on classy-prelude-0.5.0 which failed to
install.
keter-0.4.0 depends on classy-prelude-0.5.0 which failed to install.
```

Classy-prelude seems to be importing  module 'Data.IORef.Lifted'.
 And 'Data.IORef.Lifted' module exports lifted-base-0.2.1.0.

should be fixed by adding dependency of lifted-base in keter.cabal.