Pin every GitHub Action to a commit SHA

.github/workflows/ci.yml

@@ -5,12 +5,17 @@ on:
     branches: [main]
   pull_request:
 
+# CI needs nothing but source. The release workflow, which does need to write,
+# declares that on the jobs that publish.
+permissions:
+  contents: read
+
 jobs:
   build-and-test:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-go@v5
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
+      - uses: actions/setup-go@40f1582b2485089dde7abd97c1529aa768e1baff # v5
         with:
           go-version-file: go.mod
       - name: Build

.github/workflows/release.yml

@@ -15,7 +15,7 @@ jobs:
       contents: write
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
 
       - name: Create release and publish the install script
         env:
@@ -61,9 +61,9 @@ jobs:
             goos: darwin
             goarch: arm64
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
 
-      - uses: actions/setup-go@v5
+      - uses: actions/setup-go@40f1582b2485089dde7abd97c1529aa768e1baff # v5
         with:
           go-version-file: go.mod
 
@@ -120,7 +120,7 @@ jobs:
       contents: read
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
 
       - name: Render the formula
         env: