Bump GitHub actions to v4

Author: brainsik

.github/workflows/main.yml

@@ -6,26 +6,26 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: pip cache
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: ~/.cache/pip
           key: ${{ runner.os }}-pip-${{ hashFiles('ci/requirements.txt') }}
           restore-keys: |
             ${{ runner.os }}-pip-
 
       - name: pre-commit cache
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: ~/.cache/pre-commit
           key: ${{ runner.os }}-pre-commit-${{ hashFiles('.pre-commit-config.yaml') }}
           restore-keys: |
             ${{ runner.os }}-pre-commit-
 
       - name: ~/bin cache
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: ~/bin
           key: ${{ runner.os }}-homebin-${{ hashFiles('ci/versions.sh') }}