Merge pull request #4 from fluent-plugins-nursery/ci-update-workflow

ci: update workflow

Author: kenhys

.github/dependabot.yml

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

.github/workflows/linux-test.yaml

@@ -22,9 +22,9 @@ jobs:
 
     name: Ruby ${{ matrix.ruby-version }} capability ${{ matrix.capability }} on ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
       - name: Set up Ruby
-        uses: ruby/setup-ruby@v1
+        uses: ruby/setup-ruby@a6b46b8a08edb18935835849f2a17072d5cc8c73 # v1.192.0
         with:
           ruby-version: ${{ matrix.ruby-version }}
       - name: Install dependencies