Bump GHC 9.6.6 for workflows

Author: ffaf1

.github/workflows/bootstrap.yml

@@ -30,7 +30,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        ghc: ["9.0.2", "9.2.8", "9.4.8", "9.6.4", "9.8.2"]
+        ghc: ["9.0.2", "9.2.8", "9.4.8", "9.6.6", "9.8.2"]
         include:
           - os: macos-latest
             ghc: "9.2.8"

.github/workflows/validate.yml

@@ -71,7 +71,7 @@ jobs:
           [
             "9.10.1",
             "9.8.2",
-            "9.6.4",
+            "9.6.6",
             "9.4.8",
             "9.2.8",
             "9.0.2",

Makefile

@@ -226,7 +226,7 @@ bootstrap-json-%: phony
 	cd bootstrap && cabal run -v0 cabal-bootstrap-gen -- linux-$*.plan.json \
 		| python3 -m json.tool > linux-$*.json
 
-BOOTSTRAP_GHC_VERSIONS := 9.0.2 9.2.8 9.4.8 9.6.4 9.8.2
+BOOTSTRAP_GHC_VERSIONS := 9.0.2 9.2.8 9.4.8 9.6.6 9.8.2
 
 .PHONY: bootstrap-jsons
 bootstrap-jsons: $(BOOTSTRAP_GHC_VERSIONS:%=bootstrap-json-%)