chore: upgrade go to `1.21.9` (#12861)

.github/actions/setup-go/action.yaml

@@ -4,7 +4,7 @@ description: |
 inputs:
   version:
     description: "The Go version to use."
-    default: "1.21.5"
+    default: "1.21.9"
 runs:
   using: "composite"
   steps:

.github/workflows/ci.yaml

@@ -228,7 +228,7 @@ jobs:
         with:
           # This doesn't need caching. It's super fast anyways!
           cache: false
-          go-version: 1.21.5
+          go-version: 1.21.9
 
       - name: Install shfmt
         run: go install mvdan.cc/sh/v3/cmd/shfmt@v3.7.0

dogfood/Dockerfile

@@ -8,7 +8,7 @@ FROM ubuntu:jammy AS go
 
 RUN apt-get update && apt-get install --yes curl gcc
 # Install Go manually, so that we can control the version
-ARG GO_VERSION=1.21.5
+ARG GO_VERSION=1.21.9
 RUN mkdir --parents /usr/local/go
 
 # Boring Go is needed to build FIPS-compliant binaries.