github: disable Go dep updates through dependabot

We now use gobump to manage Go dependencies.  gobump supports holding
back dependency updates that require newer go compiler versions than the
one specified in the project's go.mod.

.github/dependabot.yml

@@ -1,5 +1,4 @@
-# Basic test trying dependabot
-
+---
 version: 2
 updates:
 
@@ -11,16 +10,3 @@ updates:
       time: "04:00"
     open-pull-requests-limit: 5
     rebase-strategy: "disabled"
-
-  # Maintain dependencies for Go
-  - package-ecosystem: "gomod"
-    directory: "/"
-    schedule:
-      interval: "daily"
-      time: "04:00"
-    groups:
-      go-deps:
-        patterns:
-          - "*"  # group all dependency updates into one PR
-    open-pull-requests-limit: 1
-    rebase-strategy: "auto"