update to our current CI best practices

.github/dependabot.yml

@@ -1,11 +1,8 @@
-# Set update schedule for GitHub Actions
-# See https://docs.github.com/en/free-pro-team@latest/github/administering-a-repository/keeping-your-actions-up-to-date-with-dependabot
-
+# Dependabot configuration file.
 version: 2
-updates:
 
-- package-ecosystem: "github-actions"
-  directory: "/"
-  schedule:
-    # Check for updates to GitHub Actions every weekday
-    interval: "daily"
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "monthly"

.github/workflows/test-package.yml

@@ -14,8 +14,8 @@ jobs:
     strategy:
       fail-fast: false
     steps:
-      - uses: actions/checkout@v3
-      - uses: dart-lang/setup-dart@v1
+      - uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b
+      - uses: dart-lang/setup-dart@6a218f2413a3e78e9087f638a238f6b40893203d
         with:
           sdk: dev
       - id: install