ci: use sha pinning to mitigate

Signed-off-by: Shizuo Fujita <fujita@clear-code.com>

Author: Watson1978

.github/workflows/linux.yml

@@ -25,8 +25,8 @@ jobs:
           - ubuntu-latest
     name: Ruby ${{ matrix.ruby }} unit testing on ${{ matrix.os }}
     steps:
-    - uses: actions/checkout@v6
-    - uses: ruby/setup-ruby@v1
+    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+    - uses: ruby/setup-ruby@4dc28cf14d77b0afa6832d9765ac422dbf0dfedd # v1.298.0
       with:
         ruby-version: ${{ matrix.ruby }}
     - name: unit testing

.github/workflows/stale-actions.yml

@@ -7,7 +7,7 @@ jobs:
   stale:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/stale@v10
+    - uses: actions/stale@b5d41d4e1d5dceea10e7104786b73624c18a190f # v10.2.0
       with:
         repo-token: ${{ secrets.GITHUB_TOKEN }}
         days-before-stale: 30