Go: re-add Dependabot allow list

Author: mbg

.github/dependabot.yml

@@ -22,5 +22,8 @@ updates:
     directory: "go/extractor"
     schedule:
       interval: "daily"
+    allow:
+      - dependency-name: "golang.org/x/mod"
+      - dependency-name: "golang.org/x/tools"
     reviewers:
       - "github/codeql-go"