Bump dependency versions

[philderbeast]

I tested that this package can be built with ghc-8.10.7 and ghc-9.2.4. I didn't attempt to fix warnings but did see these (and would be happy to fix them too):

> cabal build all --enable-tests --enable-benchmarks
...
src/Servant/Yaml.hs:1:14: warning: [-Wdeprecated-flags]
    -XAutoDeriveTypeable is deprecated: Typeable instances are
     created automatically for all types since GHC 8.2.
  |
1 | {-# LANGUAGE AutoDeriveTypeable    #-}
  |              ^^^^^^^^^^^^^^^^^^
...
example/Main.hs:14:1: warning: [-Wunused-imports]
    The import of ‘Network.Wai’ is redundant
      except perhaps to import instances from ‘Network.Wai’
    To import instances alone, use: import Network.Wai()
   |
14 | import           Network.Wai
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^...