Don't run hlint on testdata directories (haskell#3901)

* Don't run hlint on testdata directories

* Bump hlint version

* Remove quotes

* Ignore test data directories in .hlint.yaml

---------

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
Co-authored-by: Michael Peyton Jones <[email protected]>
Co-authored-by: Patrick Wales <[email protected]>

Author: 4 people

.github/workflows/hlint.yml

@@ -15,7 +15,7 @@ jobs:
     - name: 'Installing'
       uses: rwe/actions-hlint-setup@v1
       with:
-        version: '3.5'
+        version: '3.6.1'
 
     - name: 'Checking code'
       uses: rwe/actions-hlint-run@v2

.hlint.yaml

@@ -5,6 +5,10 @@
 # To run HLint do:
 # $ hlint --git -j4
 
+# Ignore all lints in testdata directories, as they are distracting.
+- ignore: { "within": '**/testdata/**' }
+- ignore: { "within": '**/test/data/**' }
+
 # Warnings currently triggered by our code
 - ignore: {name: "Use <$>"}
 - ignore: {name: "Use :"}