MNT: Use hash for Action workflow versions and update, and add depend…

…abot, if needed

.github/dependabot.yml

@@ -0,0 +1,16 @@
+# To get started with Dependabot version updates, you'll need to specify which
+# package ecosystems to update and where the package manifests are located.
+# Please see the documentation for all configuration options:
+# https://docs.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
+
+version: 2
+updates:
+  - package-ecosystem: "github-actions" # See documentation for possible values
+    directory: ".github/workflows" # Location of package manifests
+    schedule:
+      interval: "monthly"
+    groups:
+      actions:
+        patterns:
+          - "*"
+

.github/workflows/build.yml

@@ -8,7 +8,7 @@ on:
 
 jobs:
   build:
-    uses: OpenAstronomy/github-actions-workflows/.github/workflows/publish_pure_python.yml@v1
+    uses: OpenAstronomy/github-actions-workflows/.github/workflows/publish_pure_python.yml@924441154cf3053034c6513d5e06c69d262fb9a6  # v1.13.0
     with:
       upload_to_pypi: ${{ (github.event_name == 'release') && (github.event.action == 'released') }}
     secrets:

.github/workflows/ci.yml

@@ -14,9 +14,9 @@ jobs:
         python-version: ["3.10", "3.11", "3.12"]
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938  # v4.2.0
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v4
+        uses: actions/setup-python@f677139bbe7f9c59b41e40162b753c062f5d49a3  # v5.2.0
         with:
           python-version: ${{ matrix.python-version }}