Group dependabot PRs (#18)

.github/dependabot.yml

@@ -9,3 +9,15 @@ updates:
     directory: "/" # Location of package manifests
     schedule:
       interval: "weekly"
+    # Create a group of dependencies to be updated together in one pull request
+    groups:
+       # Specify a name for the group, which will be used in pull request titles
+       # and branch names
+       gh-actions:
+          # Define patterns to include dependencies in the group (based on
+          # dependency name)
+          patterns:
+            # - "rubocop" # A single dependency name
+            # - "rspec*"  # A wildcard string that matches multiple dependency names
+            - "*"       # A wildcard that matches all dependencies in the package
+                        # ecosystem. Note: using "*" may open a large pull request