Bump golang from 1.21.3 to 1.21.4

Bumps golang from 1.21.3 to 1.21.4.

---
updated-dependencies:
- dependency-name: golang
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.21.3
+FROM golang:1.21.4
 
 RUN git clone https://go.googlesource.com/go /tmp/golang-tip