update actions versions (remove deprecation warnings)

.github/workflows/main.yml

@@ -20,8 +20,8 @@ jobs:
         python-version: ["3.7", "3.8", "3.9", "3.10", "3.11"]
 
     steps:
-      - uses: "actions/checkout@v2"
-      - uses: "actions/setup-python@v2"
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
         with:
           python-version: "${{ matrix.python-version }}"
       # Cache the installation of Poetry itself, e.g. the next step. This prevents the workflow
@@ -30,7 +30,7 @@ jobs:
       # manually if/when you want to upgrade Poetry, or if something goes wrong. This could be
       # mildly cleaner by using an environment variable, but I don't really care.
       - name: cache poetry install
-        uses: actions/cache@v2
+        uses: actions/cache@v3
         with:
           path: ~/.local
           key: poetry-1.4.2-0
@@ -53,7 +53,7 @@ jobs:
       # them in the cache key. I'm not, so it can be simple and just depend on the poetry.lock.
       - name: cache deps
         id: cache-deps
-        uses: actions/cache@v2
+        uses: actions/cache@v3
         with:
           path: .venv
           key: pydeps-${{ hashFiles('**/poetry.lock') }}