build: Set up Dependabot to manage HashiCorp-owned GitHub Actions versioning (#35124)

.github/dependabot.yml

@@ -0,0 +1,23 @@
+version: 2
+updates:
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: monthly
+    labels:
+      - dependencies
+      - build
+      - security
+    reviewers:
+      - hashicorp/terraform-core
+    # only update HashiCorp actions, external actions managed by TSCCR
+    allow:
+      - dependency-name: hashicorp/*
+    groups:
+      github-actions-breaking:
+        update-types:
+          - major
+      github-actions-backward-compatible:
+        update-types:
+          - minor
+          - patch

.github/workflows/build-terraform-cli.yml

@@ -67,7 +67,7 @@ jobs:
         run: |
           mkdir -p "$LICENSE_DIR" && cp LICENSE "$LICENSE_DIR/LICENSE.txt"
       - if: ${{ inputs.goos == 'linux' }}
-        uses: hashicorp/actions-packaging-linux@v1
+        uses: hashicorp/actions-packaging-linux@0596d94121d44bd00463ac9d245efea64ee282d0 # v1.7
         with:
           name: "terraform"
           description: "Terraform enables you to safely and predictably create, change, and improve infrastructure. It is a tool that codifies APIs into declarative configuration files that can be shared amongst team members, treated as code, edited, reviewed, and versioned."

.github/workflows/build.yml

@@ -43,7 +43,7 @@ jobs:
           echo "pkg-name=${pkg_name}" | tee -a "${GITHUB_OUTPUT}"
       - name: Decide version number
         id: get-product-version
-        uses: hashicorp/actions-set-product-version@v1
+        uses: hashicorp/actions-set-product-version@e2c49d61aff17b1280ddfe7bb031331d02ca0140 # v1.0.1
       - name: Determine experiments
         id: get-ldflags
         env:
@@ -78,7 +78,7 @@ jobs:
       - uses: actions/checkout@c85c95e3d7251135ab7dc9ce3241c5835cc595a9 # v3.5.3
       - name: Generate package metadata
         id: generate-metadata-file
-        uses: hashicorp/actions-generate-metadata@v1
+        uses: hashicorp/actions-generate-metadata@fdbc8803a0e53bcbb912ddeee3808329033d6357 # v1.1.1
         with:
           version: ${{ needs.get-product-version.outputs.product-version }}
           product: ${{ env.PKG_NAME }}
@@ -139,7 +139,7 @@ jobs:
     steps:
       - uses: actions/checkout@c85c95e3d7251135ab7dc9ce3241c5835cc595a9 # v3.5.3
       - name: Build Docker images
-        uses: hashicorp/actions-docker-build@v1
+        uses: hashicorp/actions-docker-build@f6278ea21555b4b4737e4cf366e808ba2bb59146 # v1.6.1
         with:
           pkg_name: "terraform_${{env.version}}"
           version: ${{env.version}}