ci: Upgrade actions. Add dependabot.yml.

Author: jpmckinney

.github/workflows/ci.yml

@@ -9,7 +9,7 @@ jobs:
         os: [macos-latest, windows-latest, ubuntu-latest]
         python-version: [3.8, 3.9, '3.10', '3.11', '3.12', pypy-3.9]
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python-version }}

.github/workflows/dependabot.yml

@@ -0,0 +1,6 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"

.github/workflows/lint.yml

@@ -5,7 +5,7 @@ jobs:
     if: github.event_name == 'push' || github.event.pull_request.head.repo.full_name != github.repository
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/setup-python@v4
         with:
           python-version: '3.10'

.github/workflows/pypi.yml

@@ -4,7 +4,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/setup-python@v4
         with:
           python-version: '3.10'