Upgrade to GitHub-native Dependabot

.github/dependabot.yml

@@ -0,0 +1,29 @@
+version: 2
+updates:
+- package-ecosystem: gomod
+  directory: "/"
+  schedule:
+    interval: weekly
+  open-pull-requests-limit: 10
+  assignees:
+  - gdbelvin
+  ignore:
+  - dependency-name: github.com/golang/protobuf
+    versions:
+    - 1.4.3
+    - 1.5.1
+  - dependency-name: cloud.google.com/go/spanner
+    versions:
+    - 1.13.0
+    - 1.14.1
+    - 1.15.0
+    - 1.16.0
+  - dependency-name: github.com/prometheus/client_golang
+    versions:
+    - 1.9.0
+  - dependency-name: github.com/google/go-cmp
+    versions:
+    - 0.5.4
+  - dependency-name: github.com/grpc-ecosystem/go-grpc-middleware
+    versions:
+    - 1.2.2