Fix stack on CI

.github/workflows/master.yml

@@ -95,8 +95,8 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        stack: ["2.3.1"]
-        ghc: ["8.8.4"]
+        stack: ["2.7.3"]
+        ghc: ["8.10.4"]
 
     steps:
     - uses: actions/checkout@v2

servant-docs/servant-docs.cabal

@@ -102,7 +102,7 @@ test-suite spec
 
   -- Additional dependencies
   build-depends:
-      tasty         >= 1.1.0.4  && < 1.3,
+      tasty         >= 1.1.0.4  && < 1.5,
       tasty-golden  >= 2.3.2    && < 2.4,
       tasty-hunit   >= 0.10.0.1 && < 0.11,
       transformers  >= 0.5.2.0  && < 0.6