chore(ci): group lockstep Go modules in Dependabot config (#449)

Go modules that release in lockstep get one Dependabot PR each, and every
merge rewrites native/go.mod and go.sum, so the sibling PRs conflict.
Group OpenTelemetry, Kubernetes and golang.org/x updates into one PR each.

Signed-off-by: Marc Nuri <marc@marcnuri.com>

Author: manusa

.github/dependabot.yml

@@ -15,6 +15,13 @@ updates:
     directory: "/native"
     schedule:
       interval: "daily"
+    groups:
+      opentelemetry:
+        patterns: ["go.opentelemetry.io/*"]
+      kubernetes:
+        patterns: ["k8s.io/*", "sigs.k8s.io/*"]
+      golang-x:
+        patterns: ["golang.org/x/*"]
   - package-ecosystem: "github-actions"
     directory: "/"
     schedule: