ci: Allow Dependabot to update github.com/hashicorp/go-getter (#946)

Signed-off-by: James Alseth <james@jalseth.me>

.github/dependabot.yml

@@ -20,6 +20,8 @@ updates:
       - dependency-name: "github.com/moby/buildkit"
       - dependency-name: "github.com/spdx/tools-golang"
       - dependency-name: "github.com/subosito/gotenv"
+      # go-getter is used to fetch remote policies from various sources which occasionally has security fixes
+      - dependency-name: "github.com/hashicorp/go-getter"
     schedule:
       interval: "daily"