Update the cache action in the github workflow

Author: adithyaov

.github/workflows/haskell.yml

@@ -250,7 +250,7 @@ jobs:
     steps:
     - uses: actions/checkout@v2
 
-    - uses: actions/cache@v1
+    - uses: actions/cache@v4
       name: Cache common directories
       with:
         path: |

.github/workflows/packdiff.yml

@@ -19,7 +19,7 @@ jobs:
         ./ghcup set ghc $GHCVER
         cabal update
 
-    - uses: actions/cache@v2
+    - uses: actions/cache@v4
       name: Cache ~/.cabal
       with:
         path: |

.github/workflows/regression-check.yml

@@ -74,7 +74,7 @@ jobs:
         ./ghcup set ghc $GHCVER
         cabal update
 
-    - uses: actions/cache@v2
+    - uses: actions/cache@v4
       name: Cache ~/.cabal
       with:
         path: |