Allow lens-5.0 (#1426)

servant-docs/servant-docs.cabal

@@ -59,7 +59,7 @@ library
     , hashable             >= 1.2.7.0  && < 1.4
     , http-media           >= 0.7.1.3  && < 0.9
     , http-types           >= 0.12.2   && < 0.13
-    , lens                 >= 4.17     && < 4.20
+    , lens                 >= 4.17     && < 5.1
     , string-conversions   >= 0.4.0.1  && < 0.5
     , universe-base        >= 1.1.1    && < 1.2
     , unordered-containers >= 0.2.9.0  && < 0.3

servant-foreign/servant-foreign.cabal

@@ -52,7 +52,7 @@ library
   -- Here can be exceptions if we really need features from the newer versions.
   build-depends:
       base-compat >= 0.10.5  && < 0.12
-    , lens        >= 4.17    && < 4.20
+    , lens        >= 4.17    && < 5.1
     , http-types  >= 0.12.2  && < 0.13
 
   hs-source-dirs:      src