Use a shallow clone for submodules in Netlify

Author: Tim Bannister

netlify.toml

@@ -4,7 +4,7 @@
 # DO NOT REMOVE THIS (contact @kubernetes/sig-docs-leads)
 publish = "public"
 functions = "functions"
-command = "git submodule update --init --recursive && make non-production-build"
+command = "git submodule update --init --recursive --depth 1 && make non-production-build"
 
 [build.environment]
 HUGO_VERSION = "0.70.0"
@@ -16,13 +16,13 @@ HUGO_ENV = "production"
 HUGO_ENABLEGITINFO = "true"
 
 [context.deploy-preview]
-command = "git submodule update --init --recursive && make deploy-preview"
+command = "git submodule update --init --recursive --depth 1 && make deploy-preview"
 
 [context.branch-deploy]
-command = "git submodule update --init --recursive && make deploy-preview"
+command = "git submodule update --init --recursive --depth 1 && make deploy-preview"
 
 [context.master]
 # This context is triggered by the `master` branch and allows search indexing
 # DO NOT REMOVE THIS (contact @kubernetes/sig-docs-leads)
 publish = "public"
-command = "git submodule update --init --recursive && make production-build"
+command = "git submodule update --init --recursive --depth 1 && make production-build"