Fix regression with data uris in 2.19.1.

In 2.19.1 we used the base64URL encoding rather than base64.
This works in Safari, apparently, but not in other browsers.

Closes #8239.

src/Text/Pandoc/Class/IO.hs

@@ -36,7 +36,7 @@ module Text.Pandoc.Class.IO
 
 import Control.Monad.Except (throwError)
 import Control.Monad.IO.Class (MonadIO, liftIO)
-import Data.ByteString.Base64.URL (decodeBase64Lenient)
+import Data.ByteString.Base64 (decodeBase64Lenient)
 import Data.ByteString.Lazy (toChunks)
 import Data.Text (Text, pack, unpack)
 import Data.Time (TimeZone, UTCTime)

src/Text/Pandoc/Readers/FB2.hs

@@ -25,7 +25,7 @@ TODO:
 module Text.Pandoc.Readers.FB2 ( readFB2 ) where
 import Control.Monad.Except (throwError)
 import Control.Monad.State.Strict
-import Data.ByteString.Lazy.Base64.URL
+import Data.ByteString.Lazy.Base64
 import Data.Functor
 import Data.List (intersperse)
 import qualified Data.Map as M

src/Text/Pandoc/Readers/HTML.hs

@@ -27,7 +27,7 @@ import Control.Applicative ((<|>))
 import Control.Monad (guard, msum, mzero, unless, void)
 import Control.Monad.Except (throwError, catchError)
 import Control.Monad.Reader (ask, asks, lift, local, runReaderT)
-import Data.Text.Encoding.Base64.URL (encodeBase64)
+import Data.Text.Encoding.Base64 (encodeBase64)
 import Data.Char (isAlphaNum, isLetter)
 import Data.Default (Default (..), def)
 import Data.Foldable (for_)

src/Text/Pandoc/SelfContained.hs

@@ -19,7 +19,7 @@ import Codec.Compression.GZip as Gzip
 import Control.Applicative ((<|>))
 import Control.Monad.Trans (lift)
 import Data.ByteString (ByteString)
-import Data.ByteString.Base64.URL (encodeBase64)
+import Data.ByteString.Base64 (encodeBase64)
 import qualified Data.ByteString.Char8 as B
 import qualified Data.ByteString.Lazy as L
 import qualified Data.Text as T

src/Text/Pandoc/Writers/FB2.hs

@@ -21,7 +21,7 @@ module Text.Pandoc.Writers.FB2 (writeFB2)  where
 import Control.Monad (zipWithM)
 import Control.Monad.Except (catchError, throwError)
 import Control.Monad.State.Strict (StateT, evalStateT, get, gets, lift, liftM, modify)
-import Data.ByteString.Base64.URL (encodeBase64)
+import Data.ByteString.Base64 (encodeBase64)
 import Data.Char (isAscii, isControl, isSpace)
 import Data.Either (lefts, rights)
 import Data.List (intercalate)