ci: bump to golangci-lint v2.0

The new configuration file was initially generated by golangci-lint
migrate, when tweaked to minimize and simplify.

golangci-lint v2 switches to a new version of staticcheck which shows
much more warnings. Some of them were fixed by a few previous commits,
and the rest of them are disabled.

In particular, ST1005 had to be disabled (an attempt to fix it was made
in https://github.com/opencontainers/runc/pull/3857 but it wasn't
merged).

Also, golangci-extra was modified to include ALL staticcheck linters.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

.golangci-extra.yml

@@ -3,13 +3,19 @@
 #
 # For the default linter config, see .golangci.yml. This config should
 # only enable additional linters not enabled in the default config.
+version: "2"
 
 run:
   build-tags:
     - seccomp
 
 linters:
-  disable-all: true
+  default: none
   enable:
     - godot
     - revive
+    - staticcheck
+  settings:
+    staticcheck:
+      checks:
+        - all