Bump base to 4.14

Just as it says on the box.

Libraries:

• array: ghc/packages/array!3 (merged)
• directory: https://github.com/haskell/directory/pull/99
• deepseq: https://github.com/haskell/deepseq/pull/52
• filepath: https://github.com/haskell/filepath/pull/74
• exceptions: https://github.com/ekmett/exceptions/pull/74, https://github.com/ekmett/exceptions/pull/75
• haskeline: https://github.com/judah/haskeline/pull/122
• hpc: https://gitlab.haskell.org/ghc/packages/hpc/merge_requests/6
• parsec: https://github.com/haskell/parsec/pull/112
• process: https://github.com/haskell/process/pull/162
• stm: https://github.com/haskell/stm/pull/26
• terminfo: https://github.com/judah/terminfo/pull/35
• unix: https://github.com/haskell/unix/pull/138
• haddock:
• hsc2hs: https://github.com/haskell/hsc2hs/pull/38