github: Allow dependabot to file PRs

It will automatically open PRs to update go.mod, tools/go.mod and
.github/workflows when there are version changes.

github.com/openshift/* and k8s.io/* are ignored as these updates can be
tricky, and we want to stick to the versions corresponding to the
openshift bundle we are releasing crc with.

Signed-off-by: Christophe Fergeau <cfergeau@redhat.com>

.github/dependabot.yml

@@ -0,0 +1,19 @@
+version: 2
+updates:
+- package-ecosystem: gomod
+  directory: "/"
+  schedule:
+    interval: daily
+  open-pull-requests-limit: 10
+  ignore:
+    - dependency-name: "github.com/openshift/*"
+    - dependency-name: "k8s.io/*"
+- package-ecosystem: gomod
+  directory: "/tools"
+  schedule:
+    interval: weekly
+  open-pull-requests-limit: 10
+- package-ecosystem: "github-actions"
+  directory: "/"
+  schedule:
+    interval: "weekly"