[API Change] Rename pandocVersion to pandocVersionText...

and add a new `pandocVersion` value with type `Version`. This is
consistent with the type used for `pandocTypesVersion` and allows to use
the value where a Version type is required.

pandoc-server/src/Text/Pandoc/Server.hs

@@ -85,7 +85,7 @@ cliOptions =
   , Option ['v'] ["version"]
       (NoArg (\_ -> do
         prg <- getProgName
-        putStrLn $ prg <> " " <> T.unpack pandocVersion
+        putStrLn $ prg <> " " <> T.unpack pandocVersionText
         exitWith ExitSuccess))
       "version info"
 
@@ -208,7 +208,7 @@ server = convertBytes
     :<|> convertJSON
     :<|> mapM convertJSON
     :<|> babelmark  -- for babelmark which expects {"html": "", "version": ""}
-    :<|> pure pandocVersion
+    :<|> pure pandocVersionText
  where
   babelmark text' from' to' standalone' = do
     res <- convertText def{