Upgrade GH actions to use Node 20 features instead of 16

GH Actions have deprecated the use of Node 16, since it has reached
the end of its lifetime. Consequently, the outdated actions should
be upgraded. In case of Picireny, the checkout, setup-java and
setup-python actions need to be updated (v4 for checkout and
setup-java, and v5 for setup-python).

.github/workflows/main.yml

@@ -9,13 +9,13 @@ jobs:
         python-version: [3.8, 3.9, '3.10', '3.11', '3.12', 'pypy-3.9']
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 0
-      - uses: actions/setup-python@v4
+      - uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
-      - uses: actions/setup-java@v3
+      - uses: actions/setup-java@v4
         with:
           java-version: 17
           distribution: temurin
@@ -26,10 +26,10 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 0
-      - uses: actions/setup-python@v4
+      - uses: actions/setup-python@v5
         with:
           python-version: '3.x'
       - run: pip install --upgrade tox
@@ -38,10 +38,10 @@ jobs:
   cov:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 0
-      - uses: actions/setup-python@v4
+      - uses: actions/setup-python@v5
         with:
           python-version: '3.x'
       - run: pip install --upgrade tox coveralls
@@ -54,10 +54,10 @@ jobs:
     needs: [test, lint]
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 0
-      - uses: actions/setup-python@v4
+      - uses: actions/setup-python@v5
         with:
           python-version: '3.x'
       - run: pip install --upgrade tox