treewide: switch to gomod and bump everything

This switches version resolution from fietsje to gomod and updates
all Go dependencies. It also bumps rules_go (required by gVisor) and
switches the Gazelle naming convention from go_default_xxx to the
standard Bazel convention of the default target having the package
name.

Since Kubernetes dropped upstream Bazel support and doesn't check in
all generated files I manually pregenerated the OpenAPI spec. This
should be fixed, but because of the already-huge scope of this CL
and the rebase complexity this is not in here.

Change-Id: Iec8ea613d06946882426c2f9fad5bda7e8aaf833
Reviewed-on: https://review.monogon.dev/c/monogon/+/639
Reviewed-by: Sergiusz Bazanski <serge@monogon.tech>
Reviewed-by: Leopold Schabel <leo@nexantic.com>
diff --git a/metropolis/installer/test/testos/BUILD b/metropolis/installer/test/testos/BUILD
index 0dcb8cb..9445e21 100644
--- a/metropolis/installer/test/testos/BUILD
+++ b/metropolis/installer/test/testos/BUILD
@@ -35,15 +35,15 @@
 )
 
 go_library(
-    name = "go_default_library",
+    name = "testos_lib",
     srcs = ["main.go"],
     importpath = "source.monogon.dev/metropolis/installer/test/testos",
     visibility = ["//visibility:private"],
-    deps = ["@org_golang_x_sys//unix:go_default_library"],
+    deps = ["@org_golang_x_sys//unix"],
 )
 
 go_binary(
     name = "testos",
-    embed = [":go_default_library"],
+    embed = [":testos_lib"],
     visibility = ["//visibility:public"],
 )