Remove unneeded package dependencies from benchmark target.

pandoc.cabal

@@ -843,12 +843,9 @@ benchmark benchmark-pandoc
   main-is:         benchmark-pandoc.hs
   hs-source-dirs:  benchmark
   build-depends:   bytestring,
-                   containers,
-                   -- gauge       >= 0.2     && < 0.3,
                    tasty-bench >= 0.2     && <= 0.4,
                    mtl         >= 2.2     && < 2.3,
                    text        >= 1.1.1.0 && < 1.3,
-                   time,
                    deepseq
   -- we increase heap size to avoid benchmarking garbage collection:
   ghc-options:     -rtsopts -with-rtsopts=-A8m -threaded